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Infant vocalizations : a developmental analysis of selected prosodic features Hanford, Barbara M. 1972

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INFANT VOCALIZATIONS: A DEVELOPMENTAL ANALYSIS OF SELECTED PROSODIC FEATURES BY Barbara M. Handford B.A., University of British Columbia, 1969 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Paediatrics Division of Audiology and Speech Sciences We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA July, 1972 In p resen t i ng t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree tha t the L i b r a r y sha l l make i t f r e e l y a v a i l a b l e f o r reference and s tudy. I f u r t h e r agree t h a t permiss ion f o r ex tens ive copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s understood that copying o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not be al lowed w i t h o u t my w r i t t e n pe rm iss ion . Di;vi;si:on of A u d r o l o g y and Speech- Sciences-Department o f • Paed i;atri;cs  The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada Date August 9... 19.72. ABSTRACT Non-crying utterances of six 5- to 16-week-old infants recorded in their home environments are analyzed spectrographically for funda-mental frequency (F Q) and duration. Biographical and perceptual data are used qualitatively to suggest reasons for in t r a - and inter-subject v a r i a b i l i t y . Three major s t a t i s t i c a l analyses were performed: (1) regressions of acoustic features on age, (2) relationship of F Q and duration, and (3) contrasts of the child's fundamental frequency i n different con-texts . Not a l l regressions of acoustic features on chronological age were significant. However, two trends were evident: (1) exponential i n -crease of duration on age and (2) linear increase of within-utterance range on age. With chronological age as a basis for analysis, inter-subject v a r i a b i l i t y was noted even for these trends. Since neither development nor environment are completely uniform within or among children, developmental and social data might provide a firmer basis for analysis i n future. The result that children of the same chrono-logical age vocalized differently simply by number of utterances fur-ther supports the need for quantitative developmental and social data as analytical c r i t e r i a . Analysis of fundamental frequency by duration generally showed that frequency range was dependent on amount of fluctuation and dura-tion of utterance. A more complex analysis of the F Q-contour than i i i i i can be provided spectrographically might yield more definitive informa-tion about this relationship. The child's vocal interaction with his environment was analyzed both qualitatively and quantitatively. A frequency count of the number of utterances i n different contexts revealed that most children vocal-ized more when alone than i n the presence of an object or person. 2 Hotelling's T tests of fundamental frequency i n different contexts showed further that children did not alter the F Q-contour or within-utterance range of their vocalizations as a response to different ob-2 jects or situations. However, the fact that twenty percent of the T tests were significant — particularly for the most advanced subject — demonstrates that these children are at least capable of altering their fundamental frequency according to different situations during the early weeks of l i f e . Further research i s indicated i n this as well as i n the other areas. A l l trends noted i n this study w i l l have to be reviewed i n the context of the larger project from which the present sample of six subjects was drawn. TABLE OF CONTENTS Page ABSTRACT i i TABLE OF CONTENTS i v LIST OF TABLES i x LIST OF FIGURES x i i ACKNOWLEDGMENTS • xiv Chapter 1 INTRODUCTION 1 1.1 I n t r o d u c t i o n 1 1.2 L i t e r a t u r e Review..... 6 1.21 General C h i l d Development...... 6 1.22 Language Development S t u d i e s . . . 1 6 1.211 T h e o r e t i c a l L i n g u i s t i c S t u d i e s . . . . . . 1 6 1.222 E m p i r i c a l L i n g u i s t i c S t u d i e s 2 5 1.223 S t u d i e s of the I n f l u e n c e of E x t r a l i n g u i s t i c Fac-t o r s on Vocal Development 5 1 1.3 Summary and Statement of the Problem.. 59 Chapter 2 METHOD 6 1 2.1 Experimental Design.. «... 6 1 2.2 S u b j e c t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3 2.21 Sex and Age 6 3 2.22 Me d i c a l H i s t o r y 63 2.23 P s y c h o l o g i c a l Development 6 5 i v V Page 2.2k F a m i l i a l Environment and B i o -g r a p h i c a l I n f o r m a t i o n 67 2 . 3 Procedure 74 2 . 3 1 Data C o l l e c t i o n 74 2.311 I n s t r u m e n t a t i o n 74 2 .312 General Taping S i t u a t i o n 74 2 .313 S p e c i f i c Taping S i t u a -t i o n 75 2 .32 S p e c t r o g r a p h i c A n a l y s i s . . . . . . . . . 75 2 . 3 2 1 I n s t r u m e n t a t i o n 75 2 .322 S e l e c t i o n and C l a s s i f i -c a t i o n of Utterances 75 2 . 3 2 3 P r o d u c t i o n of S p e c t r o -grams 82 2 .33 Measurement of Fundamental F r e -quency and D u r a t i o n f o r the F i r s t Subject (CAB) 83 2 . 3 3 1 I n t r a - o b s e r v e r and I n t e r -observer R e l i a b i l i t y . . . . 86 2 . 3 ^ Measurement of Fundamental F r e -quency and D u r a t i o n f o r Other Subje c t s . , 87 v i Page Chapter 3 RESULTS 89 3 . 0 D e f i n i t i o n of Age L e v e l and I n t e r p r e -t a t i o n of R e s u l t s . . . . . . 89 3.1 D u r a t i o n 89 3.11 Comparison of Ut t e r a n c e s w i t h g i One and Two M i d d l e - p o i n t s . 3.2 Fundamental Frequency 93 3.21 W i t h i n - u t t e r a n c e Range.......... 104 3 . 3 Regression of W i t h i n - u t t e r a n c e Range on D u r a t i o n . \QQ 3,k Utterances a c c o r d i n g to Context 108 3.^1 H o t e l l i n g ' s T 2 T e s t s of Context C o n t r a s t s f o r Fundamental F r e -quency 118 3*5 Summary of R e s u l t s . . . . 131 Chapter k DISCUSSION 133 * * . l L i m i t a t i o n s of Experiment 133 J+.11 Subject Sample..... 133 *K12 C l a s s i f i c a t i o n of Data 133 4-. 13 Measurement.............. • 134 k.lk S t a t i s t i c a l A n a l y s i s 134 4-.2 Correspondence of the Present A n a l y s i s w i t h Previous F i n d i n g s 135 4-.21 D u r a t i o n . . . 135 v i i Page k.22 Fundamental Frequency 138 4.23 Context C o n t r a s t s of Utterances ( H o t e l l i n g ' s T 2 T e s t s ) 140 k.3 R e l a t i o n of P e r c e p t u a l and B i o g r a p h i c a l Data to Q u a n t i t a t i v e F i n d i n g s 143 <+.31 Outstanding Subject 143 i f . 32 D i s c u s s i o n of S p e c i f i c F i n d i n g s . . . 143 I m p l i c a t i o n s f o r Theory and Future Research 149 k.kl P r o d u c t i o n 149 k.k2 P r o d u c t i o n and P e r c e p t i o n s Context C o n t r a s t s . . . 151 ^ . 5 Summary ......... 152 REFERENCES 155 APPENDIX A I n t r a - o b s e r v e r R e l i a b i l i t y 162 APPENDIX B L i n e a r Regressions of L o g Q of D u r a t i o n on Age................... 163 APPENDIX C L o g e of D u r a t i o n and W i t h i n - u t t e r -ance Range: B a r t l e t t ' s Test f o r Homogeneity of V a r i a n c e . . 170 APPENDIX D Student's t - T e s t s of D u r a t i o n and W i t h i n - u t t e r a n c e Range f o r U t t e r -ances w i t h One and Two M i d d l e -p o i n t s 172 v i i i Page APPENDIX E Fundamental Frequency: Means and Standard D e v i a t i o n s f o r B e g i n n i n g -p o i n t , M i d d l e - p o i n t , End-point, and Derived Means 176 APPENDIX F L i n e a r Regressions of Fundamental Frequency on Age.................... 181 APPENDIX G L i n e a r Regressions of W i t h i n - u t t e r -ance Range on Age............ 206 APPENDIX H L i n e a r Regressions of W i t h i n - u t t e r -ance Range on D u r a t i o n f o r U t t e r -ances w i t h One and Two M i d d l e -p o i n t s 213 LIST OF TABLES Table Page 1.1 R e l a t i o n of C e r t a i n Developmental M i l e s t o n e s to Vocal Development d u r i n g the F i r s t Year of L i f e 3 2 1 .2 Summary of Lynip's R e s u l t s i n a Developmental Sp e c t r o g r a p h i c A n a l y s i s of a C h i l d ' s U t t e r -ances up to 52 weeks 35 1.3 Summary of Mural's Observations on I n f a n t V o c a l Development 39 l.k Summary of Nakazima's Observations on I n f a n t Vocal Development 41 1 . 5 Summary of D e s c r i p t i v e S t a t i s t i c s f o r S e l e c t e d A c o u s t i c Parameters of Neonatal C r y i n g 44 1.6 A t t r i b u t e s of I n f a n t C r i e s as found by Wasz-Hflckert et a l . (1968) 47 1.7 Average Fundamental Frequency of C h i l d r e n ' s B a b b l i n g and Speech versus Average Funda-mental Frequency of C h i l d r e n ' s C r y i n g . . . . . . . . 57 2.1 Me d i c a l H i s t o r y of I n f a n t s 64 2 . 2 R e s u l t s of Bayley T e s t s of I n f a n t Develop-ment: MDl/PDI 66 2 . 3 Education, Occupation, and Income of F a m i l i e s 68 2.1+ Parents: B i o g r a p h i c a l I n f o r m a t i o n . . . . . . . . . . . 70 ix X Page 2.5 Mean Scores f o r Parents on Heimler Scale of S o c i a l F u n c t i o n i n g (Rev. II) 72 2.6 P h y s i c a l Environment 73 2.7 Taping S e s s i o n s : CAB 76 2.3 Taping S e s s i o n s : AMG 77 2.9 Taping S e s s i o n s : AMR 78 2.10 Taping S e s s i o n s : JLR 79 2.11 Taping S e s s i o n s : DAE 80 2.12 Taping S e s s i o n s : MJK 81 2.13 I r i t r a - o b s e r v e r R e l i a b i l i t y : A n a l y s i s of Variance f o r Fundamental Frequency (CAB)... 88 2.1^ I n t e r - o b s e r v e r R e l i a b i l i t y : A n a l y s i s of Variance f o r Fundamental Frequency (CAB)... 88 3.1 D u r a t i o n : Means and Standard D e v i a t i o n s . . . 90 3.2 Student's t - T e s t s of D u r a t i o n i n Utterances w i t h One versus Two M i d d l e - p o i n t s . . 94 3.3 Student's t - T e s t s of W i t h i n - u t t e r a n c e Range i n Utterances w i t h One versus Two M i d d l e -p o i n t s 107 3.4- H o t e l l i n g ' s T 2 T e s t s of Context C o n t r a s t s f o r Fundamental Frequency: CAB............ 120 3.5 H o t e l l i n g ' s T 2 T e s t s of Context C o n t r a s t s f o r Fundamental Frequency: AMG..... 122 x i Page 3.6 H o t e l l i n g ' s T 2 Tests of Context C o n t r a s t s f o r Fundamental Frequency: AMR.... 123 3.7 H o t e l l i n g ' s T 2 Tests of Context C o n t r a s t s f o r Fundamental Frequency: JLR. 124 3.8 H o t e l l i n g ' s T 2 Tests of Context C o n t r a s t s f o r Fundamental Frequency: DAE............ 126 3.9 H o t e l l i n g ' s T 2 t e s t s of Context C o n t r a s t s f o r Fundamental Frequency: MJK. . . . • • 127 4-.1 Comparison of Present F i n d i n g s f o r D u r a t i o n and Fundamental Frequency w i t h Sheppard and Lane (1968) 137 LIST OF FIGURES F i g u r e Page 3 . 1 Regression of Log of Du r a t i o n on Age.... 92 e 3 .2 Means f o r Fundamental Frequency: CAB.... 97 3.3 Means f o r Fundamental Frequency: AMG.... 99 3.J+ Means f o r Fundamental Frequency: AMR.... 1Q0 3 . 5 Means f o r Fundamental Frequency: JLR.. •. 10.1 3 . 6 Means f o r Fundamental Frequency: DAE.... 102 3 . 7 Means f o r Fundamental Frequency: MJK.... 1Q3 3 . 8 Regression of W i t h i n - u t t e r a n c e Range on Age 105 3 . 9 Regression of W i t h i n - u t t e r a n c e Range on D u r a t i o n : Utterances w i t h One M i d d l e -p o i n t 109 3 . 1 0 Regression of W i t h i n - u t t e r a n c e Range on Du r a t i o n : Utterances w i t h Two Middl e -p o i n t s . 110 3 * 1 1 Utterances a c c o r d i n g to Context f o r CAB: Percentage over T o t a l Number of U t t e r -ances. 112 3 .12 Utterances a c c o r d i n g to Context f o r AMG: Percentage over T o t a l Number of U t t e r -ances...... 113 3 .13 Utterances a c c o r d i n g to Context f o r AMR: Percentage over T o t a l Number of U t t e r -ances 114 x i i x i i i F i g u r e Page 3.1k Utterances a c c o r d i n g to Context f o r JLR: Percentage over T o t a l Number of U t t e r -ances . 115 3.15 Utterances a c c o r d i n g to Context f o r DAE: Percentage over T o t a l Number of U t t e r -ances.*.........* 116 3«l6 Utterances a c c o r d i n g to Context f o r MJK: Percentage over T o t a l Number of U t t e r -ances 117 ACKNOWLEDGEMENTS For t h e i r ass istance i n the preparat ion of th i s the s i s , I should l i k e to express ray grat i tude to the fo l l owing: Dr. John Delack, the i n s t i g a t o r of th i s i n t r i g u i n g project and p r i n c i p a l adv i sor , for his painstaking rev i s ions of many d r a f t s ; Dr. Brenda Fraser , Dr. Jane Hastings, and Pat Swift , f o r guiding me through the confusing maze of s t a t i s t i c s and computer ana lys i s ; Dr. John G i l b e r t , not only for his p a r t i c i p a t i o n on the Committee, but e spec ia l ly for his program, which has been a most i n s p i r i n g experience; A l l the infants and t h e i r parents for l i v e l y recordings; Judy Davis for her many hours of organizat ion and recording; Bernice Wong, for her adminis trat ion of the Bayley Scales of Infant Development; Gord McConnell , for his magical e l ec tron ic r e p a i r s ; Dr. Joyce Edwards and Dr. Andre-Pierre Benguerel , for t h e i r wisdom and encouragement; Mrs. Yorath, f or typing the manuscript; Margaret, Col leen , Heather and V i r g i n i a , my comrades-in-arms ; Wordsworth, for his poem which begins, 'My heart leaps up . . . •; and xiv X V L o u i s , my f a m i l y and f r i e n d s , f o r t h e i r p a t i e n c e and u n d e r s t a n d i n g . The r e s e a r c h r e p o r t e d h e r e i n was supported i n p a r t by the Department of N a t i o n a l H e a l t h and Welfare under F e d e r a l P u b l i c H e a l t h Research P r o j e c t No. 609-7-324 ( P r i n c i p a l I n v e s t i g a t o r : Dr. John B. D e l a c k ) . Exeunt omnes. CHAPTER 1 I n t r o d u c t i o n 1 . 1 . I n t r o d u c t i o n An i n f a n t i s born i n t o an ecosystem which has as i t s s o c i a l f o u n d a t i o n a h i g h l y complex communication system. By the age of f o u r years he i s a b l e to f u n c t i o n c r e a t i v e l y w i t h -i n t h i s system. The f a c i l i t y and r a t e w i t h which he accomp-l i s h e s t h i s has i n t r i g u e d many, whether t h e i r o b s e r v a t i o n s a r e woven i n t o o l d wives' t a l e s or s c i e n t i f i c r e p o r t s . There i s c o n f u s i o n i n b o t h data and theory about the complex phenomenon of language a c q u i s i t i o n i n the r e p o r t s of the past hundred y e a r s . B e f o r e the l a s t t hree decades, many s t u d i e s were a n e c d o t a l , based on s i n g l e c h i l d r e n . I r w i n and Chen (19**3)» r e v i e w i n g the l i t e r a t u r e , found most s t u d i e s l a c k i n g from the p o i n t s of view of sampling, r e c o r d i n g and a n a l y s i s . Recent t e c h n o l o g i c a l and t h e o r e t i c a l advances have made p o s s i b l e new methods of r e c o r d i n g and a n a l y z i n g d a t a . I n s t r u -ments such as the tape r e c o r d e r , sound sp e c t r o g r a p h , and com-put e r have been found u s e f u l f o r s t u d i e s of v o c a l development (Wasz-Hdckert et a l . , 1968; Sheppard and Lane, 1 9 6 8 ) . The t h e o r e t i c a l bases of many rec e n t s t u d i e s have been s t r o n g l y i n f l u e n c e d by l e a r n i n g theory on the one hand and the g e n e r a t i v e 1 2 grammar framework on the o t h e r . From l e a r n i n g theory has come the r e c o g n i t i o n that the c h i l d ' s l i n g u i s t i c environment p l a y s a major r o l e i n h i s language development. From the g e n e r a t i v e grammar framework has come the se a r c h f o r d i s c o v e r y of l i n g -u i s t i c r u l e s governing the c h i l d ' s a c q u i s i t i o n of language. S t u d i e s based on the g e n e r a t i v e grammar theory have been prim-a r i l y of the c h i l d ' s v e r b a l development from the time of r e c o g n i z a b l e 'word' u t t e r a n c e s ( i . e . , a pproximately one year of a g e ) . The f i r s t year of l i f e has been somewhat i g n o r e d , p o s s i b l y because of d i f f i c u l t y i n d e t e r m i n i n g l i n g u i s t i c areas i n which to se a r c h f o r rul e - g o v e r n e d b e h a v i o u r . To i g n o r e the r a p i d development of the c h i l d from b i r t h to one year i s to ign o r e fundamental i n f o r m a t i o n r e g a r d i n g p h y s i c a l , n e u r o l o g i c a l , p s y c h o l o g i c a l , s o c i a l and i n t e l l e c t u a l development which enables the i n f a n t to i n t e r a c t more and more w i t h h i s environment. A c c o r d i n g to B e r r y ( 1 9 6 9 ) , the n e u r o l o g i c a l importance of the f i r s t y e a r of l i f e can be . imputed from such f a c t s as the 'very s i g n i f i c a n t p r o l i f e r a t i o n i n the i n t e r c o n n e c t i o n s of c e l l s * a t t h i s time and the t r i p -l i n g of b r a i n weight i n the f i r s t two years (p. 1 3 ) . In s t u d i e s of the d e v e l o p i n g behaviour of the i n f a n t , White (1971) has noted that by s i x weeks of age, the i n f a n t i s ' a l e r t and e x p l o r i n g the world f o r the f i r s t time i n p r o t r a c t e d f a s h i o n ' (p. 8 5 ) . S p e c i f i c d e s c r i p t i o n s of v o c a l behaviour i n the f i r s t y e ar of l i f e emphasize the e v e r - i n c r e a s i n g c o m p l e x i t y of 3 v o c a l i z a t i o n s , from the b i r t h c r y to b a b b l i n g (Irwin, 1957» Murai, i 9 6 0 , 1 9 6 3 ; Nakazima, 1 9 6 2 , 1 9 6 6). L i n g u i s t s do not yet know how to r e l a t e t h i s year of q u a s i - u n i n t e l l i g i b l e v o c a l i z i n g to 'language', which evolves g r a d u a l l y i n the jnext few y e a r s . But to c i t e V e t t e r and Howell (1971) s Simply because there i s no d i r e c t p r o g r e s s i o n from a stage i n which a l l sounds are random to the stage at which a l l sounds and sound sequ-ences match those of the model, i t should not be assumed that l i n g u i s t i c a l l y r e l e v a n t behav-i o u r does not occur d u r i n g the months p r i o r to the p r o d u c t i o n of unmistakable words, (p. 3 6 ) The study of the e a r l y phases of v o c a l b e h aviour has r e l e v a n c e f o r more than the accumulation of normative l i n g -u i s t i c d a t a . The f i e l d of c h i l d development i n g e n e r a l i s , a c c o r d i n g to White (1971)» s u f f e r i n g from a l a c k of d a t a . At the p r e s e n t time, what i s necessary i s a c o m p i l a t i o n of i n f o r m a t i o n from a l l branches of the f i e l d . Furthermore, ignorance about the normal course of d e v e l -opment i m p l i e s an i n a b i l i t y to r e c o g n i z e abnormal development at an e a r l y stage. With r e s p e c t to language, the impact of d i s o r d e r on the whole c h i l d cannot be underestimated. A language d i s o r d e r may be symptomatic of some more g e n e r a l d i s o r d e r , from h e a r i n g impairment to mental r e t a r d a t i o n to some o t h e r b e h a v i o u r a l d i s o r d e r . Moreover, a language d i s -o r d e r may e v e n t u a l l y c r e a t e o t h e r problems. Since v e r b a l communication i s b a s i c to normal s o c i a l i n t e r a c t i o n , p o o r l y 4 developed communicative s k i l l s i n h i b i t proper s o c i a l i z a t i o n and, c o n v e r s e l y , the e f f e c t s of i n h i b i t e d s o c i a l i n t e r a c t i o n can be, a c c o r d i n g to s t u d i e s on d e p r i v a t i o n , f a r - r e a c h i n g w i t h r e s p e c t to the s o c i a l , e d u c a t i o n a l , and v o c a t i o n a l success of the i n d i v i d u a l . At p r e s e n t , c l i n i c a l t e s t s f o r the d i a g n o s i s o f language and speech problems a r e based on normative data which i s d e r i v e d from s t u d i e s which evi n c e t h e i r f l a w s i n sampling, r e c o r d i n g , and a n a l y s i s . For example, Templin's (1957) c r o s s -s e c t i o n a l study of a r t i c u l a t i o n , sound d i s c r i m i n a t i o n , sentence f o r m a t i o n , and vo c a b u l a r y a p p l i e s to c h i l d r e n between th r e e and e i g h t years of age on l y , i s based on an unchecked manual method of data c o l l e c t i o n , and uses c h r o n o l o g i c a l age as the s c a l e by which to measure r e s u l t s and draw c o n c l u s i o n s . No study which p u r p o r t s to g i v e i n s i g h t i n t o development can use c h r o n o l o g i c a l age as the s o l e c r i t e r i o n by which to make judgments. I t cannot be assumed that a l l c h i l d r e n develop a t i d e n t i c a l p h y s i c a l and mental r a t e s ( c f . Lenneberg, 1967, pp. 132-133, 138). When c o n s t r u c t i n g a s c a l e of v e r b a l development, d i f f e r e n c e s i n r a t e s of growth and development as w e l l as s o c i a l background should be c o n s i d e r e d . Very l i t t l e has been accomplished i n the c o n s t r u c t i o n of t e s t s of l i n g u i s t i c development f o r the f i r s t three years of l i f e . Awareness of t h i s d e f i c i e n c y l e d Bzoch and League 5 (1971) to develop a s c a l e f o r the r e c e p t i v e and e x p r e s s i v e language development of c h i l d r e n from b i r t h to t h r e e y e a r s . T h e i r t e s t , i s , however, based on the concept t h a t there are three d i s t i n c t language modes; a ' r e c e p t i v e ' or s i g n a l decod-i n g mode, an ' e x p r e s s i v e * or s i g n a l encoding mode and an i n n e r or c e n t r a l symbolic m e d i a t i o n mode (p. 15)• B e r r y (1969) has c r i t i c i z e d t h i s t r i m o d a l d i v i s i o n of language from a n e u r o l -o g i c a l s t a n d p o i n t : The a c t and v e h i c l e of t r a n s f o r m a t i o n i s c a l l e d c o d i n g , and s i n c e the a c t i s s i m u l t -aneous, c o n t i n u o u s , and i n s e p a r a b l e , the d i v i s i o n i n t o decoding and encoding seems n e u r o l o g i c a l l y unsound. Feedback c o n t r o l i s o p e r a t i v e throughout the nervous system so the code must undergo c o n s t a n t m o d i f i c a t i o n from input u n t i l the f i n a l response, (p. 97) The very assumptions of t h e i r language model are c o n t r o v e r s i a l , then. I f t h e i r t h e o r e t i c a l model i s an i n s u f f i c i e n t r e p r e s -e n t a t i o n of the language p r o c e s s , t h e i r r e s u l t s must be i n t e r -p r e t e d w i t h some r e s e r v e . Furthermore, they have d e f i n e d v o c a l development s o l e l y i n terms of c h r o n o l o g i c a l age, which, as p r e v i o u s l y mentioned, may be u n r e l i a b l e , c o n s i d e r i n g the l a r g e i n t e r - s u b j e c t v a r i a b i l i t y of growth. In sura, much remains to be d i s c o v e r e d about the norms of c h i l d language a c q u i s i t i o n . The enormity of the task cannot be underplayed. I t can o n l y be approached w i t h the a t t i t u d e t h a t the f a c t s are there; i t i s a matter of f i n d i n g them. 6 1.2. L i t e r a t u r e review 1.21. General c h i l d development Since the c h i l d ' s l i n g u i s t i c development i s but one aspect of his t o t a l development, an overview of general devel-opmental research w i l l provide background f o r the appreciation of s p e c i f i c a l l y language-oriented studies. An absolute dichotomy has been debated i n terms of the influence of nature versus nurture i n the developmental process. Most s c i e n t i s t s now hesitate to make a s t r i c t separation of hereditary and environmental influences. In developmental psychology, Piaget's theory and research, with i t s b i o l o g i c a l foundations, has encouraged the adoption of an intermediate p o s i t i o n with respect to the nature-nurture controversy. S i n c l a i r (1971) describes Piaget's point of view i n this regard: His proposal of a t h i r d p o s s i b i l i t y i s nearer to the r a t i o n a l i s t than to the empiricist hypothesis, since i t involves innate functioning; but i t does not presuppose innate structures with biogenetic programming. Every structure comes from a simpler structure.... Piaget's point of departure f o r his study of i n t e l l i g e n t functioning i s what he c a l l s coordination of  ac tions. (p.121) S i n c l a i r continues to explain that these co-ordinations of actions are defined by both functional and s t r u c t u r a l proper-t i e s . The two basic functional properties are the c h i l d ' s a b i l i t y to incorporate new experience into an already estab-l i s h e d behaviour pattern ( i . e . , 'assimilation') and then, 7 to behave subsequently i n accordance w i t h the newly est a b -l i s h e d p a t t e r n ( i . e . , 'accommodation*). These p r o p e r t i e s are components of the c h i l d ' s b i o l o g i c a l a d a p t a t i o n to h i s su r r o u n d i n g s . The two b a s i c s t r u c t u r a l p r o p e r t i e s are o r d e r i n g of movements and h i e r a r c h i c a l s u b o r d i n a t i o n of movements. They r e f l e c t the o r g a n i z a t i o n necessary f o r the c h i l d to f u n c t i o n i n h i s environment. With these g e n e r a l concepts as the b a s i s f o r study/, P i a g e t has t r i e d to d e l i n e a t e 'stages* of c o g n i t i v e develop-ment, each stage b e i n g d i s t i n g u i s h e d by ' s t r u c t u r a l c r i t e r i a , t h a t i s , by the presence or absence of p a r t i c u l a r l o g i c a l o p e r a t i o n s which are p o s t u l a t e d to account f o r the c o g n i t i v e b e h a v i o u r at a g i v e n s t a g e ' (Shore, 1 9 7 0 , p. 1 3 9 ) . S i n c e t h i s review i s p r i m a r i l y concerned w i t h the p e r i o d of i n f a n c y , i t may be of i n t e r e s t to d e s c r i b e b r i e f l y the 'sensorimotor' stage which l a s t s u n t i l the end of the second y e a r . At b i r t h , c e r t a i n r e f l e x e s are p r e s e n t and w i t h e x e r c i s e they become p r o g r e s s i v e l y more r e f i n e d u n t i l the c h i l d f u n c -t i o n s w i t h * an e n t i r e l y p r a c t i c a l i n t e l l i g e n c e based on the m a n i p u l a t i o n of o b j e c t s ' ( P i a g e t , 1 9 6 7 . p. 1 1 ) . Near the end of t h i s stage the i n f a n t l e a r n s to separate h i m s e l f i n t e l l -e c t u a l l y and b e h a v i o u r a l l y from h i s environment. In conjunc-t i o n w i t h t h i s s e p a r a t i o n , the c h i l d becomes capable of rep-r e s e n t a t i o n of the ' e x t e r n a l ' world i n h i s ' i n t e r n a l ' con-8 c e p t u a l i z a t i o n of i t . I t i s only when t h i s 'symbolic' thought has developed that he can a c q u i r e language, a more advanced s c h e m a t i z a t i o n of the ' e x t e r n a l ' world ( P i a g e t , 196?, p. 92). In s p i t e of the f a c t t h a t P i a g e t ' s work has i n f l u e n c e d the t h e o r e t i c a l view of many developmental p s y c h o l o g i s t s on the n a t u r e - n u r t u r e c o n t r o v e r s y , much e m p i r i c a l r e s e a r c h con-t i n u e s to be e i t h e r a d i s c o v e r y of i n n a t e c a p a c i t i e s or a study of the e f f e c t s of environmental v a r i a b l e s . S t u d i e s more i n v o l v e d w i t h the d i s c o v e r y of the i n n a t e c a p a c i t i e s a r e , f o r example, those on p e r c e p t i o n , e s p e c i a l l y v i s u a l p e r c e p t i o n . White (1971) s t a t e s : The c u r r e n t view ... i s t h a t the newborn i n f a n t i s capable of f a r more d i f f e r e n t i a t e d v i s u a l f u n c t i o n than p r e v i o u s l y b e l i e v e d , (p. l6) Kagan (1970), b a s i n g h i s developmental hypotheses on v i s u a l s t u d i e s , has observed t h a t a neonate has been 'equipped w i t h an i n i t i a l b i a s i n the p r o c e s s i n g of e x p e r i e n c e ' . The f i r s t e x p e r i e n t i a l r e p r e s e n t a t i o n s i n b r a i n , the 'schemes' are those of ' i n v a r i a n t s t i m u l u s p a t t e r n s t h a t are p a r t of a l a r g e r c o n t e x t c h a r a c t e r i z e d by h i g h r a t e of change' (p. 828). The f i r s t a l t e r a t i o n of the schemes Kagan d e s c r i b e s w i t h the • d i s c r e p a n c y p r i n c i p l e ' : ' s t i m u l i moderately d i s c r e p a n t from the schema e l i c i t l o n g e r o r i e n t a t i o n s than do e i t h e r m i n i m a l l y d i s c r e p a n t ... events or novel events that bear no r e l a t i o n to the schema' (p. 828). 9 Few s t u d i e s have been c a r r i e d out f o r the other sensory-m o d a l i t i e s . Of a u d i t i o n , White (1971) r e p o r t s that 'the g e n e r a l p i c t u r e i s t h a t , as i n the case of v i s i o n , the newborn i s a b l e to f u n c t i o n i n rudimentary f a s h i o n (p. l 6 ) . Very l i t t l e has been s p e c i f i c a l l y c onfirmed, however. One study i n t h i s area i s that of Eimas et a l . (1971 )f on i n f a n t speech p e r c e p t i o n . They f e l t t h a t they had evidence t h a t one and four-month-old i n f a n t s c o u l d d i s c r i m i n a t e c a t e g o r -i c a l l y between v o i c e d and unvoiced l a b i a l stops i n the same manner as a d u l t s , i . e . , a l o n g an a c o u s t i c continuum. They drew the c o n c l u s i o n that such p e r c e p t i o n c o u l d be b i o l o g i c a l l y determined. However, the i n f a n t s were a l r e a d y a t l e a s t one month of age and had t h e r e f o r e had c o n s i d e r a b l e exposure to t h e i r l i n g u i s t i c environment, i . e . , they may have l e a r n e d the d i s t i n c t i o n s . Furthermore, i t has been demonstrated by P r e s t o n et a l . (1967) t h a t , i n d i f f e r e n t languages, phoneme boundaries are found i n d i f f e r e n t l o c a t i o n s a l o n g the a c o u s t i c continuum. Extending the h y p o t h e s i s of Eimas et a l . , the d i s c r i m i n a t i o n of v o i c e d versus unvoiced l a b i a l stops would have to be i n n a t e l y d i f f e r e n t f o r d i f f e r e n t languages. T h i s seems u n l i k e l y , e s p e c i a l l y c o n s i d e r i n g the f a c i l i t y w i t h which c h i l d r e n can l e a r n more than one language at an e a r l y age. A more ge n e r a l c r i t i c i s m can be made of the above study, which a p p l i e s to many s t u d i e s on i n f a n t p e r c e p t i o n , both a u d i t o r y and v i s u a l . One of the major d i f f i c u l t i e s w i t h the 10 p e r c e p t u a l s t u d i e s i s the r e l i a b l e d e t e r m i n a t i o n of the i n f a n t ' s response to an impinging s t i m u l u s . A p r e s e n t a t i o n of a s t i m u l u s to an i n f a n t may r e s u l t i n a b e h a v i o u r a l change ( f i x a t i o n , v o c a l i z a t i o n , s m i l i n g , i n c r e a s e d movement) or a p h y s i o l o g i c a l change (change i n c a r d i a c r a t e , n o n - n u t r i t i v e s u c k i n g r a t e ) . Upon repeated p r e s e n t a t i o n of the s t i m u l u s , the c h i l d may • h a b i t u a t e ' to the s t i m u l u s , i n which cases there i s a s i g n i f -i c a n t response decrement a c r o s s t r i a l s . A new s t i m u l u s may subsequently i n c r e a s e response r a t e or s t r e n g t h . I f t h i s sequence o c c u r s , the i n f a n t i s presumed to have p e r c e i v e d the s t i m u l u s . I t has, however, never been adequately demonstrated t h a t there i s a one-to-one r e l a t i o n between sti m u l u s and response. B e h a v i o u r a l m a n i f e s t a t i o n s of response are dependent upon ob s e r v e r s e p a r a t i o n of random behaviour and response behaviour, i . e . , endogenous vs exogenous s t i m u l a t i o n ( c f . L i n g , L i n g , and Doehring, 1 9 7 0 , and L i n g , 1 9 7 0 ) . R e l i a b i l i t y i s , then, a p p a r e n t l y poor f o r t h i s index of response. P h y s i o l o g i c a l m a n i f e s t a t i o n s of response may be s l i g h t l y more r e l i a b l e than b e h a v i o u r a l ones, s i n c e more o b j e c t i v e measurement can be made. N e v e r t h e l e s s , there i s disagreement as to the b e s t index of response f o r c a r d i a c r a t e , i . e . , whether a c c e l e r a t i o n , d e c e l e r a t i o n , or mere v a r i a b i l i t y ( c f . Kaplan, 1 9 7 0 ) . A c c o r d i n g to Kaye (1967) 11 s t u d i e s which employ the n o n - n u t r i t i v e s u c k i n g index o f t e n f a i l to account f o r such v a r i a b l e s as s u c k i n g d e p r i v a t i o n , f o o d d e p r i v a t i o n , v a r i a t i o n s i n a r o u s a l s t a t e , p h y s i o l o g i c a l p a t h ology, sudden onset of an extraneous s t i m u l u s , c o n d i t i o n -i n g , e t c . I t i s to be noted t h a t Eimas et a l . (1971) f a i l e d to mention these sources of e r r o r , a l t h o u g h they used the index of n o n - n u t r i t i v e s u c k i n g i n t h e i r study. In sum, i t appears t h a t the above i n d i c e s of response are s t i l l too vaguely d e f i n e d to be v a l i d and r e l i a b l e measures. Although the b e h a v i o u r a l and p h y s i o l o g i c a l changes may be i n some way connected w i t h the st i m u l u s i n p u t , i t has not y e t been demonstrated t h a t they are r e l a t e d i n a d i r e c t cause and e f f e c t manner. Many s t u d i e s have been c a r r i e d out on the d i r e c t e f f e c t of environment upon development, ba t h from the p o i n t of view of s t i m u l a t i o n and d e p r i v a t i o n . Environmental v a r i a b l e s have some advantage over g e n e t i c ones i n t h a t they can be manipu-l a t e d and c o n t r o l l e d to some extent (Fowler, 1970, p. 1^1). Fowler d e s c r i b e s environment and experience as bot h p h y s i o l -o g i c a l and p s y c h o l o g i c a l , the former b e i n g p r e - , p e r i - , and p o s t n a t a l n u t r i t i o n , e x e r c i s e and p h y s i c a l trauma, the l a t t e r b e i n g p h y s i c a l and s o c i a l forms of s t i m u l a t i o n (p. 1^2). Although he admits that i t i s d i f f i c u l t to know the e f f e c t s of socioeconomic and c u l t u r a l v a r i a b l e s on development, he 12 e s t a b l i s h e s t h a t ' c h i l d - r e a r i n g methods 1 , 'communication modes•, and the 'general l e a r n i n g atmosphere and degree of language f o c u s i n the home' are r e l a t e d b o t h to i n t e l l e c t u a l a b i l i t i e s and l e a r n i n g processes (p. 1 ^ 2 ) . Thus, the non-verbal and v e r b a l r e l a t i o n s h i p of the c h i l d to h i s p arents seems to have r e l e v a n c e f o r the c o g n i t i v e development of the c h i l d . Freeberg and Payne (1967) r e a c h much the same c o n c l u s i o n s i n t h e i r summary of s t u d i e s on the e f f e c t of environmental v a r i a b l e s on i n t e l l e c t u a l f u n c t i o n i n g ; they admit the l a c k of s t u d i e s on c o r r e l a t i o n of s o c i o - c u l t u r a l v a r i a b l e s and s p e c i f i c c o g n i t i v e s k i l l s (p. 7 6 ) . Two examples of such s t u d i e s are those by Irwin (1957) and by E n t w i s l e ( 1 9 6 8 ) . Irwin's study of phoneme a c q u i s i t i o n i n c l u d e s an a n a l y s i s of the e f f e c t s of sex, r a c e , and o c c u p a t i o n a l s t a t u s on the d e v e l -opment of speech. No d i f f e r e n c e s were found f o r sex and r a c e ; p a r e n t a l o c c u p a t i o n a l s t a t u s seemed to have some e f f e c t a f t e r f i f t e e n months on the r a t e of a c q u i s i t i o n of sound types, those c h i l d r e n from non-labourer homes a c q u i r i n g phoneme types a t a f a s t e r r a t e (p. k l ) . E n t w i s l e (1968) attempted to c o r r e l a t e s u b c u l t u r a l v a r i a b l e s w i t h w o r d - a s s o c i a t i o n l e v e l s . Whether or not these s t u d i e s are v a l i d i n the t o t a l framework of such s t u d i e s , there does appear to be a t r e n d s u g g e s t i n g t h a t a r e l a t i v e l y u n s t i m u l a t i n g environment h i n d e r s i n t e l l e c t u a l development. 13 S p e c i f i c s t u d i e s on the e f f e c t of d e p r i v a t i o n have, a c c o r d i n g to C a l d w e l l ( 1 9 7 0 ) , undergone two phases, the •maternal d e p r i v a t i o n ' phase and the ' c u l t u r a l d e p r i v a t i o n * phase (pp. 2 6 3 - 2 6 4 ) . The m a j o r i t y of these s t u d i e s (e.g., D e c a r i e , 1 9 6 5 ; U z g l r i s and Hunt, 1964; C a l d w e l l and Richmond, I 9 6 7 ) have been r e t r o s p e c t i v e or f i e l d s t u d i e s y i e l d i n g i n c o n -s i s t e n t r e s u l t s . As was s t a t e d e a r l i e r , Irwin (1957) found that environmental v a r i a b l e s were onl y of major import f o r r a t e of a c q u i s i t i o n of phoneme types a f t e r the age of f i f t e e n months. Fowler (1970) s t a t e s that l i n e a r - t y p e s c a l e s such as Irwin's or the l a t e r B ayley S c a l e s of I n f a n t Development (1969) may f a i l to e l u c i d a t e the d i f f e r e n c e s between advantaged and disadvantaged c h i l d r e n a t an e a r l y age. He c i t e s the example of the U z g i r i s and Hunt (1967) s c a l e , a P i a g e t i a n s c a l e of s t a g e - l i n k e d o p e r a t i o n s , which has p o i n t e d to s i g n i f i c a n t trend d i f f e r e n c e s between advantaged and disadvantaged i n f a n t s as e a r l y as e l e v e n months (p. 143). E x p e r i m e n t a l l y c o n t r o l l e d s t u d i e s of the e f f e c t of s t i m -u l a t i o n on development have a l s o been c a r r i e d out. The e n r i c h -ment programs of Rheingold (1956) are one such example. I n s t i t -u t i o n a l i z e d c h i l d r e n were d i v i d e d i n t o two groups, one of which was e x p e r i m e n t a l l y 'mothered' and the o t h e r of which was not. E a r l y enrichment was found to produce temporary and c o n c u r r e n t changes i n the e n r i c h e d group of c h i l d r e n , but once the s t i m -u l a t i o n was removed, the unenriched group a c h i e v e d the same 14 l e v e l of performance; the enrichment e f f e c t was, f o r the purpose of the study, not long-term. One s i g n i f i c a n t d i f f e r -ence between •enriched* and 'unenriched' babies was a g r e a t e r amount of v o c a l i z a t i o n i n the 'enriched* ones. A s i m i l a r experiment on three groups of c h i l d r e n two and o n e - h a l f y ears of age was undertaken by Cazden (1965). In one group, an a d u l t *expanded* ( i . e . , i m i t a t e d w i t h a d u l t grammar) on the c h i l d ' s v e r b a l response to a p i c t u r e book; i n the second group, the a d u l t p r e s e n t e d 'models' ( i . e . , added d i v e r s e comments) to the c h i l d a f t e r h i s v e r b a l response; no s p e c i a l treatment was g i v e n to the t h i r d group. The r e s u l t s i n d i c a t e d t h a t the f i r s t two groups gained i n l i n g u i s t i c performance, p a r t i c u l a r l y the group who r e c e i v e d ' m o d e l l i n g ' treatment. Whether or not m o d e l l i n g or expansion i s a more e f f e c t i v e form of s t i m u l a t i o n i s as y e t unknown a c c o r d i n g to M c N e i l l (1970). However, i t does appear t h a t s t i m u l a t i o n has at l e a s t a s h o r t -term e f f e c t on l i n g u i s t i c development. What t h i s s i g n i f i e s i n terms of f u t u r e l i n g u i s t i c development and i n t e l l e c t u a l growth has not been determined. C o r r e l a t i o n s between e a r l y and l a t e r performance have been drawn, based on t o t a l I . Q . s c o r e s and on r e l a t i v e l y independent t a s k s . Cameron et a l . (1967) d e s c r i b e d one of the l a t t e r type of c o r r e l a t i o n s . Six r e l a t i v e l y indep-endent item c l u s t e r s were chosen from the C a l i f o r n i a F i r s t Year Mental S c a l e , a p r e c u r s o r to the B a y l e y S c a l e p r e v i o u s l y mentioned. A datum was c o n s i d e r e d to the c h i l d ' s f i r s t p a s s i n g 15 of an item. S i g n i f i c a n t c o r r e l a t i o n s were found f o r females o n l y between e a r l y v o c a l i z a t i o n s and l a t e r v e r b a l I.Q. (pp. 3 3 1 - 3 3 2 ) . In the environmental s t u d i e s mentioned, the environment appeared to have an e f f e c t on the c h i l d ' s c o g n i t i v e develop-ment. Language s t i m u l a t i o n p a r t i c u l a r l y seems to p l a y an important r o l e . However, i t seems c l e a r t h a t much remains to be c l a r i f i e d i n t h i s area of r e s e a r c h . In summary of t h i s c u r s o r y overview of g e n e r a l develop-mental s t u d i e s , i t w i l l be u s e f u l to p r e s e n t White's ( l 9 7 l ) o u t l i n e of i n f a n t behaviour up to age s i x months, as f o l l o w s : B i r t h to s i x weeks: The t y p i c a l s t a t e of the i n f a n t i s s l e e p or d rowsiness. C e r t a i n s e m i - f u n c t i o n a l r e f l e x e s are a v a i l a b l e to him, p a r t i c u l a r l y the s t a r t l e , the grasp, and the r o o t i n g responses. At t h i s stage, he i s not e a s i l y c o n d i t i o n e d (pp. 8 3 - 8 ! * ) . S i x weeks to 3*5 months: T h i s p e r i o d 'might be c h a r a c t e r i z e d as the dawning of awareness and v o l u n t a r y a c t i o n 1 • For exam-p l e , the c h i l d gains some mastery of h i s hands and becomes a b l e to f o cus on o b j e c t s and people. At t h i s stage he can be con-d i t i o n e d more r e a d i l y (p. 8 5 ) . 3o5 months to 6 months: The major achievement of t h i s p e r i o d i s 1 v i s u a l l y - d i r e c t e d reaching' . Babies of t h i s age seem to be 'euphoric' , s m i l i n g and l a u g h i n g r e a d i l y . Since they are more capable of u s i n g t h e i r hands and eyes, they i n t e r a c t much more w i t h the environment ( p . 8 6 ) . 16 1.22. Language development s t u d i e s As was noted i n the i n t r o d u c t i o n , the f i r s t year of l i f e i s the l e a s t researched p e r i o d w i t h r e s p e c t to v o c a l develop-ment. Those analyses which have been made may be c l a s s i f i e d i n t o two g e n e r a l c a t e g o r i e s : l i n g u i s t i c and e x t r a l i n g u i s t i c . Two g e n e r a l l i n g u i s t i c i s s u e s a r e : (1) the r o l e of nature versus nurture i n the a c q u i s i t i o n of language (2) the r e l e v a n c e of the v o c a l behaviour of the f i r s t year f o r language development S p e c i f i c i s s u e s i n c l u d e : (1) the q u e s t i o n of order i n the p r o d u c t i o n of sounds (2) the q u e s t i o n of meaningful e x p r e s s i o n (3) the r o l e of p r o s o d i e s (such as i n t o n a t i o n ) i n language development. E x t r a l i n g u i s t i c s t u d i e s examine the r o l e of environment i n the c h i l d ' s v e r b a l development. Some of these were mentioned i n the p r e v i o u s s e c t i o n . 1.221. T h e o r e t i c a l l i n g u i s t i c s t u d i e s Nature versus nurture i n the l i n g u i s t i c c ontext T h e o r i e s of the ontogenesis of language have been i n f l u -enced by g e n e r a l t h e o r i e s of c h i l d development. The nature-nurture c o n t r o v e r s y has been debated i n d i v i d u a l l y by Chomsky, the major proponent of the n a t i v i s t p o i n t of view, and Skinner, 17 the major proponent of the e m p i r i c i s t p o i n t of view. Chomsky proposes an a b s t r a c t i n p u t - o u t p u t model -- the language a c q u i s i t i o n d e v i c e (LAD) — to account f o r the a c q u i -s i t i o n of language. I t i s h i s o p i n i o n that the nature of the output ( i . e . , knowledge or l i n g u i s t i c ' c o m p e t e n c e 1 ) must be determined b e f o r e an h y p o t h e s i s can be c o n s t r u c t e d to account f o r the i n n a t e mechanisms of the LAD (1967* pp. 2 - 3 ) . F u r t h e r -more, c e r t a i n f a c t s w i t h r e s p e c t to language a c q u i s i t i o n must, a c c o r d i n g to Chomsky, be c o n s i d e r e d i n the c o n s t r u c t i o n of the model: (1) Although the language i n p u t of the c h i l d i s l i m i t e d and i m p e r f e c t ( i n t h a t i t c o n t a i n s f a l s e s t a r t s , h e s i t a t i o n s , ungrammatical u t t e r a n c e s , e t c . ) , the c h i l d l e a r n s to produce an u n l i m i t e d number of grammatical u t t e r a n c e s , a l b e i t w i t h h i s own i d i o s y n c r a t i c anomalies. (2) 'A g r e a t d i v e r s i t y of input c o n d i t i o n s does not l e a d to a wide d i v e r s i t y i n r e s u l t i n g competences'. (But c f . Hymes, 1970 ) (3) The a c q u i s i t i o n of language i s very r a p i d and occurs at a very e a r l y age. (196"7i p. 4 ) To account f o r these f a c t s , Chomsky d e f i n e s competence (the output) as 'a system of r e c u r s i v e r u l e s that p r o v i d e the b a s i s f o r the c r e a t i v e aspect of language use and that manipulate h i g h l y a b s t r a c t s t r u c t u r e s ' (1967» p. 7 ) . He then deduces that t h i s system i s a consequence of the d e s i g n of the LAD, and, 18 f u r t h e r , t h at the components of t h i s LAD might be: (1) Both a phonetic and a semantic theory to d e f i n e the c l a s s e s of p o s s i b l e phonetic and semantic r e p r e s e n t a t i o n s ; (2) A schema that d e f i n e s the c l a s s of p o s s i b l e grammars; (3) A method of i n t e r p r e t i n g i n p u t data i n the co n t e x t of p o s s i b l e grammars; and (k) A method of e v a l u a t i n g the grammars to choose the one most compatible w i t h the d a t a . (1967> p» 8) Chomsky's e x p l a n a t i o n of both competence and the LAD are s u b j e c t to c r i t i c i s m . A c c o r d i n g to Hymes (1971). Chomsky's d e f i n i t i o n of competence i s too a b s t r a c t and narrow i n scope because i t does not i n f a c t account f o r the r e a l speaker-hearer s i t u a t i o n w i t h a l l i t s e r r o r s of performance and i t s s o c i o -c u l t u r a l v a r i a b l e s . I t cannot be assumed t h a t t h e r e are not i n a c t u a l i t y a g r e a t d i v e r s i t y of competences, s i n c e competence i s such an a b s t r a c t model to t e s t . I f an i n n a t e LAD i s p o s t -u l a t e d , i t can indeed be deduced that competence i s a t l e a s t l i m i t e d by the c o n s t r a i n t s of the d e v i c e . However, the d e v i c e i t s e l f c o n t a i n s so many sub-models and t h e o r i e s that i t can onl y be c o n s i d e r e d a very t e n t a t i v e s c h e m a t i z a t i o n of the c l a s s of p o s s i b l e p r o c e s s e s . Such a h i g h l y evolved s c h e m a t i z a t i o n as the LAD may be a product of a s i m p l e r and more i n c l u s i v e t h e o r y . Skinner's a p p l i c a t i o n of the operant c o n d i t i o n i n g model to the develop-ment of v e r b a l behaviour c o u l d not be c o n s i d e r e d such a theory. 19 However, s i n c e i t i s an u n t e s t e d e x t r a p o l a t i o n of data and terminology from animal s t u d i e s to human l i n g u i s t i c b e h a v i o u r , i t s v a l i d i t y can be s e r i o u s l y q u e s t i o n e d . Chomsky has c r i t i c -i z e d the theory on the grounds that i t cannot account f o r the r a p i d i t y of language a c q u i s i t i o n , nor the 'range of observed u n i f o r m i t y of output' (1965» p. 54). That experience and environmental v a r i a b l e s do p l a y a major r o l e has been i n d i c -a t e d i n the g e n e r a l developmental s e c t i o n . T h e i r r o l e may be c o n s i d e r e d o n l y one p a r t of the i n t e r a c t i o n of h e r e d i t y and environment, however. As w i t h g e n e r a l t h e o r i e s of c h i l d development, an i n t e r -mediate and a l l - i n c l u s i v e theory w i t h r e s p e c t to the nature-n u r t u r e c o n t r o v e r s y can be p o s t u l a t e d f o r the c o n t r o v e r s y i n the l i n g u i s t i c c o n t e x t . In her e x p l i c a t i o n of P i a g e t ' s theory, S i n c l a i r (1971) s t a t e s t h a t : ... l i n g u i s t i c u n i v e r s a l s e x i s t p r e c i s e l y because of the u n i v e r s a l thought s t r u c t u r e s --and these are u n i v e r s a l , not because they are in b o r n but because they are the necessary outcome of a u t o r e g u l a t o r y f a c t o r s and e q u i l -i b r a t i o n processes .... (p. 123) L i n g u i s t i c development i s viewed i n the g r e a t e r c o n t e x t of t o t a l development. Language a c q u i s i t i o n i s dependent upon c o g n i t i v e development. The r e s o l u t i o n of the n a t u r e - n u r t u r e c o n t r o v e r s y i n the l i n g u i s t i c context can thus proceed from r e s e a r c h o u t s i d e the s t r i c t l y l i n g u i s t i c a r e a . 20 Relevance of v o c a l behaviour i n the f i r s t year of l i f e f o r  the l i n g u i s t i c development of the c h i l d Any theory, the purpose of which i s to d e s c r i b e and e x p l a i n an observable p r o c e s s , normally i n v o l v e s a d i v i s i o n or c a t e -g o r i z a t i o n of the continuous process i n t o a s e r i e s of d i s c r e t e steps or stages* Many l i n g u i s t s have d e s c r i b e d the e x i s t e n c e of two b a s i c stages of language development: a p r e l i n g u i s t i c stage (from b i r t h to the end of the f i r s t y ear) and a l i n g u i s -t i c stage (which begins w i t h the appearance of the f i r s t 'word'). T h i s d i v i s i o n narrowly d e f i n e s ' l i n g u i s t i c b e h a v i o u r ' to be communicative behaviour which n e c e s s a r i l y depends on the man-i p u l a t i o n of a c c e p t a b l e but a r b i t r a r y phonemic symbols. For many r e s e a r c h e r s , a p r e l i n g u i s t i c - l i n g u i s t i c d i v i s i o n f u r t h e r i m p l i e s t h a t v o c a l behaviour which does not f u l f i l these r e q u i r e -ments i s more or l e s s meaningless i n language development. Jakobson (1968), M c N e i l l (1970), and Lenneberg (1967) make a sharp d i s t i n c t i o n between the c r y i n g , c o o i n g , and b a b b l i n g u t t e r a n c e s of the f i r s t year and the ' t r u e ' l i n g u i s t i c u t t e r -ances which b e g i n i n the second y e a r . A c c o r d i n g to Jakobson (1968), the u t t e r a n c e s of the f i r s t y e a r r e p r e s e n t n o t h i n g more than a 'purposeless e g o c e n t r i c s o l i l o q u y * , from which 'there a r i s e s and grows by degrees i n c h i l d r e n a d e s i r e f o r commun-i c a t i o n * (p. 2 4 ) . For Jakobson, the 'q u e s t i o n of the p r e l a n g -uage b a b b l i n g p e r i o d proves to be ... one of e x t e r n a l p h o n e t i c s , predominantly a r t i c u l a t o r y i n nature ...' (p. 2 7 ) . M c N e i l l 21 extends t h i s viewpoint w i t h h i s statement t h a t 'babbling, i f i t p l a y s a p a r t i n the emergence of speech, does so f a r behind the scenes* ( 1 9 7 1 , p. 1 3 0 ) . T h i s k i n d of u n s u b s t a n t i a t e d g e n e r a l statement f a i l s to c l a r i f y any p o i n t of view. Lenneberg suggests an e x p l a n a t i o n f o r a p r e l i n g u i s t i c - l i n g u i s t i c d i s c o n t i n u i t y w i t h the theory of 'language r e a d i n e s s * : b e f o r e a complex behaviour such as language can emerge, th e r e must be s u f f i c i e n t neuroanatomical and n e u r o p h y s i o l o g i c a l m a t u r a t i o n ( 1 9 6 7 , p. 3 7 6 ) . Although he emphasizes the r a p i d i t y of n e u r o p h y s i o l o g i c a l m a t u r a t i o n i n the f i r s t two y e a r s , and g i v e s an account of the changing v o c a l b e h a v i o u r which accompanies the m a t u r a t i o n of b r a i n , he more or l e s s d i s c o u n t s the v o c a l behaviour of these two years as i n e s s e n t i a l f o r development of language. The o t h e r major p o i n t of view i s , c o n v e r s e l y , t h a t v o c a l behaviour of the f i r s t y ear of l i f e does have r e l e v a n c e f o r l i n g u i s t i c development. Two p o s s i b l e f u n c t i o n s of b a b b l i n g are d e f i n e d by Fry (1966) as a r t i c u l a t o r y and phonatory ' p r a c t i c e * and as p a r t of the raw m a t e r i a l necessary f o r the b u i l d u p of an a u d i t o r y feedback l o o p (p. 188). Jakobson, d e s p i t e h i s p r e v i o u s l y mentioned statement that b a b b l i n g r e p r e s e n t s a 'purposeless e g o c e n t r i c s o l i l o q u y ' , a l s o makes t h i s s u g g e s t i o n ( 1 9 6 8 , p. 2 2 ) . Fry's f i r s t statement may be d i f f i c u l t to demonstrate e m p i r i c a l -l y , but the second may have some b e a r i n g on the f a c t t h a t 22 h a r d - o f - h e a r i n g i n f a n t s , a l t h o u g h they babble, do not develop speech, u n l e s s they r e c e i v e what i s known c l i n i c a l l y as a u d i t o r y t r a i n i n g . They have f a i l e d to r e c e i v e s u f f i c i e n t a u d i t o r y s t i m u l a t i o n from t h e i r own and o t h e r s ' v o i c e s . Both these proposed r e l e v a n c e s of b a b b l i n g r e l a t e to the development of the sound p a t t e r n of a language. Of t h i s , B e r r y notes t h a t a l t h o u g h the sounds of b a b b l i n g 'have no d i s t i n c t i v e n e s s and probably do not make up the r e p e r t o i r e from which the c h i l d l a t e r develops the phonemes of speech', 'babbling, n o n e t h e l e s s , may be v a l u a b l e as a t u n i n g up and i n t e g r a t i n g process f o r the ... organs ... to be employed i n speech* (p. l6k). Another s i g n i f i c i a n t i s s u e i n c o n j u n c t i o n w i t h the b a s i c communicative process i s touched on by Fry (1966): the e x p r e s s i o n and comprehension of meaning under whatever g u i s e . For the i n f a n t meaning i s probably a f f e c t i v e , and r e l a t e d to f e e l i n g s of comfort and d i s c o m f o r t . One of the f e a t u r e s chosen f o r the e x p r e s s i o n and comprehension of meaning i s i n t o n a t i o n , a p r o s o d i c f e a t u r e (p. 188). Other l i n g u i s t s have made s i m i l a r c l a i m s . Lewis (1936), i n h i s s i n g l e - c h i l d study, observed that d i f f e r e n t p i t c h e d c r i e s seemed to have been used f o r d i f f e r e n t emotional s t a t e s . Wasz-HOckert et a l . (1968), whose work w i l l be d i s c u s s e d i n more d e t a i l l a t e r , appear to have a c o u s t i c and p e r c e p t u a l evidence to support Lewis* o b s e r v a t i o n . B e r r y r e p o r t s that between the f o u r t h and s i x t h month, the c h i l d may roughly i m i t a t e the ' i n t o n a t i o n a l p a t t e r n of the speaker's 23 i n t e r j e c t i o n or e x p r e s s i o n of d e l i g h t ' , more to emit a p l e a s u r e -a b l e f e e l i n g than to c r e a t e a 'meaningful o r a l response' (p. 164). Again round the end of the f i r s t year, he begins to i m i t a t e u n i t s of 'meaning w i t h a l l the i n t o n a t i o n a l and rhythmic accompaniments which he has heard' (p. l64)• Weir (1966) s i m i l a r l y p o i n t s out t h a t a c h i l d ' s speech may be un-i n t e l l i g i b l e but y e t can be segmented i n t o ' s e n t e n c e - l i k e chunks* on the b a s i s of i n t o n a t i o n (p. 153 )• Lieberman (1967) i n d e s c r i b i n g the same phenomenon, goes so f a r as to propose that the i n f a n t c r y i s an ' i n n a t e l y ' determined s i g n a l by reason of i t s r e l a t i o n s h i p to the 'breath-group' of the sentence (p. Ul), an i n n a t e l y determined, s y n c h r o n i z e d s t a n d a r d p a t t e r n of a c t i v i t y wherein the r e s p i r a t o r y and l a r y n g e a l muscles a c t to produce phonation on the f l o w of e x p i r a t o r y a i r . T h i s extended h y p o t h e s i s has been s t r o n g l y c r i t i c i z e d by Kim ( 1 9 6 8 ) , a c c o r d i n g to whom, what i s ' i n n a t e ' i s r e s p i r a t i o n ; i t i s o n l y i n c i d e n t a l *to note that the l e n g t h of a c r y or a s i n g l e u t t e r a n c e normally spans the p e r i o d of e x p i r a t i o n * , s i n c e i n f a n t s a p p a r e n t l y have i n s u f f i c i e n t l a r y n g e a l c o n t r o l f o r s u b g l o t t a l p r e s s u r e i n r e l a t i o n to e x p r e s s i v e and meaning-f u l u t t e r a n c e s . Kim concludes that 'whatever mechanism under-l i e s the i n f a n t c r y may not be assumed to p r o v i d e an i n n a t e b a s i s f o r the s u b g l o t t a l p r e s s u r e contour i n the a d u l t ' s speech, s i n c e the i n f a n t c r y i s , i n t h i s sense, no more i n n a t e to speech than i t i s to s i n g i n g ...* (p. 8 3 2 ) . 24 Whether or not the c r y has an i n n a t e b a s i s i s f o r the present s t a t e of knowledge not as r e l e v a n t as the h y p o t h e s i s that i n t o n a t i o n has l i n g u i s t i c s i g n i f i c a n c e i n the f i r s t y e a r . I f one d e f i n e s language development as a p r o g r e s s i v e refinement of communicative a b i l i t y , one can p o s t u l a t e t h a t i n t o n a t i o n p a t t e r n s are a b a s i c s t r u c t u r e to which semantic, p h o n o l o g i c a l , and s y n t a c t i c f e a t u r e s are added, g i v e n the proper environmental s t i m u l a t i o n and n e u r o l o g i c a l m a t u r i t y . One might rename the •stages' of development 'the predominantly suprasegmental ( p r o s o d i c ) sound-meaning correspondence stage* and'the predom-i n a n t l y segmental sound-meaning correspondence st a g e ' . On such a b a s i s , one c o u l d indeed f i n d u t i l i t y i n the study of v o c a l development d u r i n g the f i r s t year of l i f e . 25 1.222. E m p i r i c a l l i n g u i s t i c s t u d i e s Recent t e c h n o l o g i c a l advances i n e l e c t r o n i c equipment d e s i g n have somewhat changed the scope of e m p i r i c a l i n v e s t i g a -t i o n s of v o c a l development. E a r l y s t u d i e s Those concerned w i t h the s u b j e c t of c h i l d language a c q u i s i t i o n have spend much time r e c o r d i n g the p r o d u c t i o n of i n f a n t s ' u t t e r a n c e s by k i n d (or 'type') and frequency (or •token'). M ^ s t of the s t u d i e s b e f o r e 19^0 were a n e c d o t a l , and hence incomplete and u n c o n t r o l l e d s i n g l e - c h i l d s t u d i e s . P a r e n t s , not n e c e s s a r i l y l i n g u i s t s , were u s u a l l y the o b s e r v e r s . They manually t r a n s c r i b e d s e l e c t e d u t t e r a n c e s i n i d i o s y n c r a t i c f a s h i o n w i t h l i t t l e or not r e c o u r s e to a s t a n d a r d i z e d system of phonetic t r a n s c r i p t i o n . I r w i n and Chen (19^3) reviewed these s t u d i e s and found t h e i r sampling, r e c o r d i n g and a n a l y s i s techniques l a c k i n g . I t was the o b j e c t i v e of I r w i n and Chen to r e c t i f y t h i s s i t u a t i o n by c o n d u c t i n g a comprehensive study on i n f a n t v o c a l development from b i r t h to t h i r t y months. For t h e i r sample they chose 95 i n f a n t s from m i d d l e - c l a s s homes. Not a l l c h i l d r e n were ab l e to be observed f o r the f u l l t h i r t y months. Ir w i n r e p o r t e d i n a l a t e r study that race, sex, s i b l i n g i n f l u e n c e and o c c u p a t i o n a l s t a t u s of the parents b e f o r e the 26 i n f a n t s were f i f t e e n months of age, d i d not a f f e c t the data (1957* pp. 4 1 8 - 4 1 9 ) . In the same r e p o r t , he comments on the problem of the q u a n t i f i c a t i o n of i n f a n t speech sound d a t a : The problem of q u a n t i f i c a t i o n of i n f a n t speech sound data fundamentally i s the problem of f i n d i n g s u i t a b l e u n i t s and i n d i c e s which w i l l l e n d themselves to mathematical and s t a t i s t i c a l treatment. The phoneme, which i s the elemental speech sound u n i t , i s the obvious one f o r showing the i n f a n t ' s phonetic development, (p. 4 0 5 ) • The crux of the matter l i e s i n which i n d i c e s to use. U n f o r t -u n a t e l y , I r w i n chose the term 'phoneme', which he nowhere e x p l i c i t y d e f i n e s . When one c o n s i d e r s t h a t , once a standard r e a d i n g , a phoneme i s l a n g u a g e - s p e c i f i c , the use of t h i s term i s q u e s t i o n a b l e i n the d e s c r i p t i o n of e a r l y i n f a n t u t t e r a n c e s , which have a p p a r e n t l y not y e t been marked w i t h the f e a t u r e s of a s p e c i f i c language. The F a i r b a n k s ' (19^0) m o d i f i c a t i o n of the I n t e r n a t i o n a l Phonetic Alphabet was the b a s i s f o r phonemic a n a l y s i s . I r w i n (19^5) f e l t t h a t they had c o n t r o l l e d f o r i n t e r -o b s e r v e r d i f f e r e n c e by a p r e - t e s t of r e l i a b i l i t y . I t was found t h a t : (1) f o r f r e q u e n t l y o c c u r r i n g phonemes, the c o r r e l a t i o n was over 90% between t r a n s c r i p t i o n s ; (2) f o r phonemes o c c u r r i n g of low frequency, the c o r r e l a t i o n s was a l s o low; (3) f o r c o n s o n a n t - l i k e sounds, the c o r r e l a t i o n was lower than f o r v o w e l - l i k e sounds; and (k) l e a s t agreement was found f o r those speech sounds observed 2 7 i n the f i r s t year of l i f e ( i . e . , most valu e s l e s s than 70%). The l a s t f i n d i n g e s p e c i a l l y i n d i c a t e s the weakness of the t r a n s c r i p t i o n system used. Even t r a i n e d t r a n s c r i b e r s have d i f f i c u l t y i n a g r e e i n g upon i n f a n t u t t e r a n c e s , probably s i n c e those u t t e r a n c e s are f o r e i g n to the d i a l e c t of the a d u l t o b s e r v e r . A most s e r i o u s e r r o r i s one t h a t the r e l i a b i l i t y data do not show; even i f the p h o n e t i c i a n s are i n agreement, there i s no means by which the v a l i d i t y of t h e i r t r a n s c r i p -t i o n s can be determined. Since they are t r a i n e d to hear c e r t a i n sounds, they i n t e r p r e t e d a l l sounds i n t h i s frame-work. With r e s p e c t to the sample of u t t e r a n c e s , the r e l i -a b i l i t y t e s t s were more s i g n i f i c a n t . Irwin chose to use a b e h a v i o u r - u n i t sample r a t h e r than a time sample s i n c e the l a t t e r r e s u l t e d i n j u s t over f i f t y p e r c e n t r e l i a b i l i t y . The b e h a v i o u r u n i t was a t h i r t y - b r e a t h sample of n o n - c r y i n g u t t e r a n c e s (1957* p. ^06). D e s p i t e the flaws of d e s i g n , i t i s of i n t e r e s t to summarize Irwin and Chen's f i n d i n g s , s i n c e t h e i r s was the f i r s t l a r g e - s c a l e attempt at q u a n t i f i c a t i o n of n o n - c r y i n g u t t e r a n c e s of the f i r s t two and one-half y e a r s . The r e s u l t s were summarized i n terms of phoneme type and phoneme f r e -quency. The phonemes were c a t e g o r i z e d as 'vowels' or 'conso-nants', a f t e r the a d u l t model of speech. 'Vowel' and 'consonant', as 'phoneme', must be c o n s i d e r e d only approximate r e p r e s e n t a t i o n s of the sounds emitted, s i n c e i t cannot be assumed that i n f a n t s are p r o d u c i n g u t t e r a n c e s or 28 sounds e q u i v a l e n t to a d u l t speech sounds. For the purpose of r e p o r t i n g t h e i r r e s u l t s , however, I s h a l l employ Irw i n and Chen's terminology. By phoneme type, i t was observed that vowels were f a r more fr e q u e n t i n the f i r s t y ear than consonants, but by the end of the second year, consonants exceeded the numbers of vowels. At the c o n c l u s i o n of the study, the i n f a n t s produced almost a l l the vowels of E n g l i s h , and about t w o - t h i r d s of the conson-ants (Irwin, 19^6, p. 28). I r w i n noted t h a t the vowels appeared i n a f r o n t to back o r d e r . In the neonate, 80% of the vowels'were produced i n the f r o n t of the mouth; by the end of the f i r s t y ear, the major-i t y of the vowels were back ones (19^8, p. 3 2 ). P r o d u c t i o n of consonants a c c o r d i n g to p l a c e of a r t i c u l a t i o n was i n the r e v e r s e order of the p r o d u c t i o n of vowels. In the f i r s t two months, 98% of the consonants were produced i n the back of the mouth, whereas by the end of fche f i r s t year, 50% were produced i n the f r o n t of the mouth (1947, pp. 398-399). P r o d u c t i o n of consonants a c c o r d i n g to manner of a r t i c -u l a t i o n showed a f l u c t u a t i o n of f r i c a t i v e s and p l o s i v e s a c r o s s time, a l t h o u g h they composed most of the consonant sounds. Between f i v e and s i x months, n a s a l s and g l i d e s appeared. By ten months, semi-vowels, and f r i c a t i v e s i n c r e a s e d i n number. 29 At the end of the study, the i n f a n t s * a r t i c u l a t i o n s were f a i r l y s i m i l a r to a d u l t a r t i c u l a t i o n s ( 1 9 4 7 b , p. 402 ) . For phoneme type, Irwin noted t h a t a mean a n a l y s i s c o u l d be made; there appeared to be a normal curve of produc-t i o n , w i t h d e c r e a s i n g v a r i a b i l i t y w i t h age ( 1 9 4 7 a , pp. 1 7 5 - 1 7 6 ) . I r w i n was not only i n t e r e s t e d i n type, but i n frequency. He r e p o r t e d that up to 18 months, the phoneme frequency i n -c r e a s e d a t a con s t a n t r a t e , and a f t e r t h a t , a t a f a s t e r i n c r -e a s i n g r a t e ( 1 9 4 7 a , p. 1 8 8 ) . The r a t i o of consonant to vowel was more l i n e a r f o r frequency than f o r type ( 1 9 4 6 , p. 1 7 7 ) . I r w i n noted b e s i d e s t h a t there was more v a r i a b i l i t y f o r frequency than f o r type ( 1 9 4 6 , p. 1 7 7 ) . Frequency i n c r e a s e d w i t h age u n t i l a c o n s t a n t v a r i a t i o n was reached ( 1 9 4 7 b ) . Hypotheses have been fo r m u l a t e d to e x p l a i n t h i s apparent order of p r o d u c t i o n . One of the e a r l i e s t t h e o r i e s was the • p r i n c i p l e of l e a s t e f f o r t ' as proposed by S c h u l t z e ( 1 G 8 0 ) . A c c o r d i n g to t h i s theory, the speech sounds are produced by c h i l d r e n i n an order which begins w i t h the sounds a r t i c u l a t e d w i t h the l e a s t p h y s i o l o g i c a l e f f o r t , g r a d u a l l y proceeds to the speech sounds produced w i t h g r e a t e r e f f o r t , and ends w i t h the sounds which r e q u i r e the g r e a t e s t e f f o r t f o r t h e i r p r o d u c t i o n . By p h y s i o l o g i c a l e f f o r t i s meant the amount of nerve and muscle energy needed to b r i n g about the p o s i t i o n of the speech 30 organs necessary f o r the p r o d u c t i o n of a speech sound. ( C i t e d i n Bar-Adon and Leopold, Eds., 1971. p. 28). Jakobson r e f u t e s t h i s h y p o t h e s i s on two grounds: (1) by the o v e r r i d i n g p o i n t of view t h a t there i s no o r d e r of p r o d u c t i o n of sounds; and ( 2 ) by the f a c t t h at a c h i l d can, t h e o r e t i c a l l y , w h i l e b a b b l i n g produce any p o s s i b l e sound (1968, pp. 2 0 - 2 1 ) . Assuming that there i s an order of a c q u i s i t i o n , other hypoth-eses have been proposed to e x p l a i n I r w i n and Chen's d a t a . McCarthy ( 1 9 5 2 ) o f f e r s an organismic i n t e r p r e t a t i o n of d e v e l -opment. A major p a r t of her i n t e r p r e t a t i o n i s deduced from the 'law of developmental d i r e c t i o n ' , which s t a t e s that a c t i v -i t y develops from gross to f i n e motor movement (p. 2 7 5 ) . Vowels appear i n a f r o n t to back and consonants i n a back to f r o n t d i r e c t i o n because the f r o n t vowels and back consonants i n v o l v e gross movements of %he r o o t of the tongue, whereas the back vowels and f r o n t consonants i n v o l v e f i n e r movements of the r o o t , b l a d e , and t i p of $he tongue. (More r e c e n t l y , Drachman C 1 9 7 0 ] has p o s i t e d a s i m i l a r p h y s i o l o g i c a l theory to account f o r the o r d e r of sound p r o d u c t i o n . ) McCarthy a l s o r e l a t e s develop-ment of f e e d i n g and b r e a t h i n g p a t t e r n s as w e l l as p o s t u r a l c o n t r o l to the changes i n v o c a l development, the assumption u n d e r l y i n g t h i s r e l a t i o n b e i n g t h a t as the i n f a n t a t t a i n s c e r t a i n l e v e l s of p h y s i c a l and p h y s i o l o g i c a l development, he becomes capable of more and more complex v o c a l p r o d u c t i o n . 31 Insert Table 1 .1 about here (cf. Table 1 . 1 ) . Lenneberg, although pointing out that a d i r e c t , casual r e l a t i o n s h i p between motor and speech develop-ment i s u n l i k e l y , notes that 'a picture of consistency evolves' between these two aspects of development i n normal childre n (1967 , p. 1 3 2 ) . S i m i l a r l y , Bever ( 1 9 6 l ) has reviewed the Irwin and Chen data and has attempted to co r r e l a t e neurolog-i c a l maturation and babbling. At four months, there sometimes appears to be a sudden silence i n the c h i l d . Sever correlated this with the c o r t i c a l i n h i b i t i o n s of primitive r e f l e x e s . 3e tween f i v e and eleven months, the c h i l d babbles. At the end of this time, babbling more or less subsides; this i s interpreted as the res u l t of c o r t i c a l integration taking place at this period (Bever, 1 9 6 l , c i t e d i n McNeill, 1970 , pp. 1 3 2 - 1 3 3 ) . Irwin and Chen's study, impressive by i t s scope, has stimulated discussion as to the existence, nature, and possible causes of infant sound production. A study which r e l i e s s o l e l y on perceptual observation technique, p a r t i c u l a r l y when the c r i t e r i a are derived from analysis of adult speech, must however, be accepted reservedly. TABLE 1.1 RELATION OF CERTAIN DEVELOPMENTAL MILESTONES TO VOCAL DEVELOPMENT DURING THE FIRST YEAR OF LIFE Age (mos) Vocalizations Respiration Feeding patterns Postural control Birth Many [hD Rapid, Supine only -1 mo. sounds abdominal 1-2 More varied More vocalization regular 2-3 Cooing Head erect 3-4 Decrease in Strong sucking vocalization drive 7 Babbling Spoon and cup Sitting alone 10 First Solid foods syllable 12 First word Chewing Standing alone (Based on McCarthy, 1952, pp. 273-277) 33 Instrumental s t u d i e s Improvements i n technology — w i t h the advent of the magnetic tape r e c o r d e r , the sound sp e c t r o g r a p h , the movie camera, video t a p e , and computers have changed the scope of s t u d i e s of i n f a n t sound p r o d u c t i o n . L y n i p (1951) was the f i r s t l i n g u i s t to employ the mag-n e t i c tape r e c o r d e r and sound s p e c t r o g r a p h (an audio-frequency a n a l y z e r which produces a t h r e e - d i m e n s i o n a l graphic r e c o r d of a s i g n a l ) . I t was h i s i n t e n t i o n to c r i t i c i z e the p e r c e p t u a l techniques of Irwin and Chen. He attempted to d e f i n e 'how an i n f a n t ' s random sound i s changed over a p e r i o d of time', 'when c r y i n g becomes d i f f e r e n t i a t e d ' , and 'when and how the s o c i a l environment of the i n f a n t ... i n f l u e n c e s i t s u t t e r a n c e s * (p. 2 2 9 ) . Weekly r e c o r d i n g s were made i n the home environment, s i g n i f i c a n t environmental events were noted, and a s p e c t s of growth were c o r r e l a t e d on one i n f a n t (p. 2 1 3 ) . The purpose of L y n i p ' s study was to 'serve as a p i l o t i n v e s t i g a t i o n — to show how adequate study can be g i v e n the pre-speech u t t e r a n c e s of i n f a n t s without dependence on any phonetic system and how a t e c h n i c a l a n a l y s i s of those d a t a , gathered without d i s t o r -t i o n , can now be made' (p. 2 2 9 ) . Hence, h i s r e s u l t s on t h i s one c h i l d can only serve as p r e l i m i n a r y i n s t r u m e n t a l observa-t i o n s . A c o u s t i c and p e r c e p t u a l data are i n c l u d e d i n Table 1 . 2 . 34 I n s e r t Table 1.2 about here Three g e n e r a l trends appeared i n h i s d a t a : (1 ) C r y i n g d i d not appear to be a c o u s t i c a l l y d i f f e r e n t i a t e d a c c o r d i n g to needs (but c f . Wasz-Hfl'ckert et a l . , 1968). (2 ) B e f o r e the end of the f i r s t year, there was no s i n g l e vowel or consonant sound that was a c o u s t i c a l l y compar-a b l e to an a d u l t sound. On these grounds, he c r i t i c i z e s Irwin's use of the IPA t r a n s c r i p t i o n system and j u s t i f i e s the use of a more o b j e c t i v e approach to the a n a l y s i s of i n f a n t u t t e r a n c e s . (3 ) On the spectrograms, g r a d u a l a c o u s t i c changes were marked: At f i r s t , the resonances were b l u r r e d t o g e t h e r , the frequency of the v o c a l i z a t i o n s doubled and then redoubled ( i n d i c a t i n g a l a c k of c o n t r o l ) and the beginnings and endings of sounds were i n d i s t i n c t . L a t e r p i c t u r e s show an i n c r e a s i n g d i s t i n c t i o n between resonances, a g r e a t e r c o n t r o l of tone, i n c l u d i n g a g r e a t e r t o n a l range, and more p r e c i s e shaping of sounds. (pp. 2 ^ 5 - 2 4 7 ) L y n i p ' s study has not escaped c r i t i c i s m on t h e o r e t i c a l grounds. Winitz ( i 9 6 0 , 1969) o u t l i n e s the u n r e l i a b l e and p o s s i b l e i n v a l i d f e a t u r e s of sound spectrography. E r r o r of measurement may produce poor i n t e r - r e a d e r r e l i a b i l i t y ( i 9 6 0 , p. 1 7 3 ) . ( I t has s i n c e been shown by Lindblom [ 1 9 6 2 ] that at l e a s t a 1*0 Hz e r r o r i s made each time formants are measured on 35 TABLE 1.2 SUMMARY OF LYNIP'S RESULTS IN A DEVELOPMENTAL SPECTROGRAPHIC ANALYSIS OF INFANT UTTERANCES UP TO 52 WEEKS Acoustic data Perceptual data Irregular, uncontrolled crying General features noted were pitch fundamentals, attacks and terminations, time values, rhythms, cadences, resonances, and intensities Fundamental frequency = 360 Hz Formant 1 = 720 Hz Foment 2 = 920 Hz Formant 3 = 2400 Hz Fundamental frequency = 420 Hz Formant 1 = 880 Hz Formant 2 = 1260 Hz Formant 3 = 3000 Hz Imitations of adult speech only approximations Irregular, uncontrolled crying Crying with an awareness of others' actions in the room Recognizable non-crying utterance Audible laugh Sounds strung together Attempts to imitate mother's utterances Uses a particular sound to represent a particular object Uses a particular sound to represent an object; the sound similar to adult sound for the object (Based on Lynip, 1951, pp. 234-245) 36 male voice spectrograms.) More important, there i s apparently a lack of isomorphism between the acoustic and perceptual features of sound. For example, perceptually d i f f e r e n t vowels have been found to have considerable formant frequency overlap, whereas perceptually s i m i l a r vowels have been found to have considerable v a r i a t i o n of formant regions (cf. Peterson and Barney, 1952). Research from the Haskins Laboratories has indicated that vowels and consonants influence each other i n context, so that two i d e n t i c a l bands of energy may be heard as two d i f f e r e n t consonants when juxtaposed with the two d i f f e r e n t vowels (cf. Liberman et a l . 1952, 1957. 1959). In spite of instrumental drawbacks, others have used the spectrograph i n the analysis of infant v o c a l i z a t i o n s . Murai (I960) c a r r i e d out a study along the l i n e s of Lynip's p i l o t study, but on a more intensive basis. Tape recordings were made twice monthly i n the children's homes, during t h e i r most active periods. Other developmental data were included. Wide-band spectrograms and amplitude sections were produced. The f i r s t non-crying utterance was noted to occur at about six weeks of age. This correlated well with Lynip's observation. Murai noted that this utterance had a 0.** second duration (p. 29). Onset of babbling appeared to be at about six months. General conclusions drawn were as follows: (1) Pattern of development appeared to be from simple to complex behaviour. 37 (2) C o n s o n a n t - l i k e sounds appeared to be produced i n a back to f r o n t o r d e r . (3) Vowels appeared to occur a c c o r d i n g to a p r i n c i p l e of l e a s t e f f o r t , i . e . , from lax to tense. (k) The i n t e r v a l between u t t e r a n c e s became p r o g r e s s i v e l y s h o r t e r . ( 5 ) I m i t a t i o n of sounds appeared to occur between e i g h t and ten months, (pp. 3 0 - 3 1 ) Some of Mural's r e s u l t s bear out the f i n d i n g s of I r w i n and Chen and L y n i p . However, h i s a n a l y s i s of i n f a n t speech by wide-band spectrography i s q u e s t i o n a b l e , s i n c e r e s o l u t i o n of a s i g n a l w i t h a h i g h fundamental produces l i t t l e more than harmonic r e s o l u t i o n , the e q u i v a l e n t of narrow-band r e s o l u t i o n , but l e s s d i s t i n c t . In a second r e p o r t , Murai (1963) added other s p e c t r o -g r a p h s and g e n e r a l o b s e r v a t i o n s , f o r example: (1) In the f i r s t p e r i o d of u t t e r a n c e s , there appeared to be no r e g u l a r r e l a t i o n between vowels and consonants. ( 2 ) At f i r s t the i n t e r v a l of sounds was f a i r l y r h y t h m i c a l , but over time, t h i s r h y t h m i c a l r e l a t i o n between u t t e r -ances was l o s t . (3) There were changes i n the a c o u s t i c f e a t u r e s of the sounds. (4) The p i t c h and n o i s e p a t t e r n s became jumbled as consonantal sounds appeared. 38 (5 ) In the f o u r t h month, there was *a tendency f o r the i n f a n t s to approximate a d u l t s ' u t t e r a n c e s ' . T h i s d i d not necess-a r i l y imply that the i n f a n t s were i m i t a t i n g a d u l t u t t e r -ances. Murai d e s c r i b e s the d i f f i c u l t y i n d e t e r m i n i n g which behaviour i s i m i t a t i v e , but he r e i n f o r c e s h i s s t a t e -ment i n the i 9 6 0 r e p o r t that phonetic i m i t a t i o n occurs at about the n i n t h or t e n t h month. He does not mention i m i t a t i o n of i n t o n a t i o n . (6 ) In the b a b b l i n g stage, r e p e t i t i o n s of u t t e r a n c e s appeared. Un i t u t t e r a n c e s had almost the same u t t e r i n g time as a d u l t u t t e r a n c e s (100-300 msec). (7 ) A f t e r the b a b b l i n g stage, the i n f a n t s ' sounds had reduced frequency area, a r e g u l a r i z e d r e l a t i o n between vowels and consonants, and shortened s u c c e s s i v e sounds. (1963* pp. 2 5 - 2 6 ) Q u a l i t a t i v e o b s e r v a t i o n s which r e l a t e stages of v o c a l develop-ment to s i t u a t i o n and apparent purpose are i n c l u d e d i n Table I n s e r t Table 1.3 about here Murai found a c o u s t i c parameters u s e f u l f o r t r a c i n g the p a t t e r n of development i n the c h i l d ' s p r o d u c t i o n of u t t e r a n c e s . T h i s k i n d of approach f r e e s the l i n g u i s t from a r t i c u l a t o r y phonetic r e p r e s e n t a t i o n s to d e l i n e a t e developmental p a t t e r n s and pro-TABLE 1,3 SUMMARY OF MURAI'S OBSERVATIONS ON INFANT VOCAL DEVELOPMENT Age Vocalizations Situation of utterance Purpose Birth Birth-cry Physiological First month Crying Discomfort state A 'signal' to mother to relieve needs End of first Non-crying utterance Comfort state No apparent purpose month 7-9 months Babbling; repetitive Comfort state and play Phonetic play utterances situations 12 months Symbolic meaning In relation to an object Symbolic expression (Based on Murai, 1963, pp. 19-23) 40 v i d e s a more o b j e c t i v e measure. His r e s u l t s are s t i l l some-what d e s c r i p t i v e , however; more q u a n t i f i c a t i o n would be r e q u i r e d i f t h i s data were to be v a l u a b l e as an index of development. Nakazima (1962) a l s o conducted a s p e c t r o g r a p h i c study of the development of v o c a l b e h a v i o u r . His r e s u l t s are a n a l y z e d i n terms of stages. A summary of these stages i n terms of kinds of v o c a l i z a t i o n and s i t u a t i o n of u t t e r a n c e s i s prov-i d e d i n Table 1.1*. I n s e r t Table 1.4- about here The r e s u l t s of L y n i p , Murai, and Nakazima appear to c o r r e l a t e w e l l . However, t h e i r work i s r e l a t i v e l y g e n e r a l compared w i t h more re c e n t s t u d i e s . In the l a s t few y e a r s , s e v e r a l s t u d i e s have been conducted w i t h the o b j e c t of r e f i n -i n g techniques of data c o l l e c t i o n and a n a l y s i s . An attempt to s t a n d a r d i z e data c o l l e c t i o n i s d e s c r i b e d by Bullowa, Jones and Bever (196**). The o b j e c t i v e s of t h e i r study were (1) to i d e n t i f y the segmental and suprasegmental f e a t u r e p a t t e r n s , (2) to determine the sequence of a c q u i s i t i o n of the above, (3) to observe the v o c a l i n t e r a c t i o n of the mother and the c h i l d , and (k) to r e l a t e v o c a l development to TABLE 1.4 SUMMARY OF NAKAZIMA'S OBSERVATIONS ON INFANT VOCAL DEVELOPMENT Stage Age (mos) Vocalizations Situation of utterance 1 Birth -1 mo. Crying Crying ceases when needs satisfied 2 1-2 Non-crying utterances (Rhythm of utterances = 0.6 - 0.8 seconds) Comfortable situations More vocalization in presence of mother speech 3 2-5 Duration of utterances longer High pitch variation Back vowels f i r s t , then other vowels and some consonants Variable response among children to parents 4 6-8 Repetitive babbling Front consonants Alone or in the presence of auditory stimuli, such as adult speech or animal sounds 5 9-12 Use of intonation for expression Some imitation More vocalization "in presence of adults 6 12 Phonemic sounds with symbolic content Play, expression of needs, or to communicate (Based on Nakazima, 1962, pp. 29-38) 4 2 environmental and g e n e r a l developmental f a c t o r s (p. 1 0 2 ) . For s u b j e c t s , they chose f o u r normal f i r s t b o r n i n f a n t s of normal E n g l i s h - s p e a k i n g p a r e n t s . Weekly morning tape r e c o r d -ings and f i l m s of one - h a l f hour d u r a t i o n were made i n the homes over a t h i r t y - m o n t h p e r i o d . A c h i l d p s y c h i a t r i s t noted p e r t i n e n t i n f o r m a t i o n about the r e c o r d i n g s e s s i o n s . To be a b l e to r e l a t e developmental f a c t o r s to v o c a l development, p s y c h o l -o g i c a l and medical t e s t s were a d m i n i s t e r e d f i v e times i n the f i r s t month and then monthly u n t i l the end of the study. However, the data have not been e x t e n s i v e l y analyzed nor have r e s u l t s been r e p o r t e d . Another more s p e c i f i c technique of data c o l l e c t i o n and a n a l y s i s developed i n a h o s p i t a l s e t t i n g . P r e l i m i n a r y work by K a r e l i t z et a l . ( i 9 6 0 ) i n d i c a t e d t h a t normal and abnormal i n f a n t s c o u l d be d i f f e r e n t i a t e d on the b a s i s of p i t c h and amount of -c r y i n g . The apparent d i a g n o s t i c use of the a n a l y s i s of the i n f a n t c r y encouraged others to c o n t i n u e t h i s i n v e s t i -g a t i o n . R i n g e l and K l u p p e l (196^ ) recorded and ana l y z e d the c r y of s i x female and f o u r male neonates w i t h normal h i s t o r i e s . The r e c o r d i n g s were made i n a q u i e t room w i t h a microphone p l a c e d twelve inches from the head of the i n f a n t . A c r y was e l i c i t e d w i t h a p a i n f u l s t i m u l u s . Those c r i e s which exceeded 0.5 second and 60 dB on the B r f i e l and K j a e r Sound Pres s u r e L e v e l Meter were chosen f o r a n a l y s i s . Narrow-band a n a l y s i s 43 was performed, u s i n g a constant g a i n l e v e l on playback and d o u b l i n g the speed of the r e c o r d i n g . At the midpoint of the c r y an amplitude s e c t i o n was made. Peak f r e q u e n c i e s of the formant areas were noted. The r e s u l t s o b t a i n e d f o r fundamental frequency, d u r a t i o n and i n t e n s i t y are r e p o r t e d i n Table 1 .5* I n s e r t Table 1.5 about here S i g n i f i c a n t i n t e r - s u b j e c t v a r i a t i o n was found f o r i n t e n s i t y and fundamental frequency. A g e n e r a l c o r r e l a t i o n was noted between the obtained mean fundamental frequency and that ob-t a i n e d by Fairbanks (19 * *2) , which was 373 Hz. The formant areas a l s o c o r r e l a t e d g e n e r a l l y w i t h those obtained by Pe t e r s o n and Barney ( 1952 , p. 1 2 6 ) . The two most i n t e r e s t i n g r e s u l t s of R i n g e l and Kl u p p e l ' s study are the v a r i a b l e fundamental f r e -quency and i n t e n s i t y among s u b j e c t s . I f there i s such g r e a t v a r i a b i l i t y among normal s u b j e c t s f o r these parameters, i t would be very d i f f i c u l t to determine an abnormal c r y , u n l e s s i t were f a r removed from the ends of the normal range. However, the authors have not i n c l u d e d any p h y s i o l o g i c a l or anatomical data on these p a r t i c u l a r i n f a n t s ( s i z e , weight, c i n e s t u d i e s of the l a r y n x , e t c . ) ; thus there may be a p h y s i c a l b a s i s f o r the v a r i a b i l i t y . N e i t h e r have they i n c l u d e d any other data p e r t i n e n t to the r e c o r d i n g s i t u a t i o n and occurrences which may have had some b e a r i n g on the d i f f e r e n c e s . (With r e s p e c t 44 TABLE 1.5 SUMMARY OF DESCRIPTIVE STATISTICS FOR SELECTED ACOUSTIC PARAMETERS OF NEONATAL CRYING Parameters Mean SD Range Fundamental frequency (Hz) 413.33 30.05 290-508 Duration (seconds) 1.47 .62 0.62-4.02 Sound pressure level CdB) 82.13 3.40 65.0-93.5 (Ringel and Kluppel, 1964, p.4) 45 to i n t e n s i t y measurement, they d i d not p r e c i s e l y d e f i n e which r e l a t i v e standard was used.) Of i n t e r e s t a l s o i s the f a c t that t h e r e was not a l a r g e v a r i a b i l i t y f o r d u r a t i o n ; t h i s p o s s i b l y has a p h y s i o l o g i c a l b a s i s -- due to lung c a p a c i t y , s u b g l o t t a l p r e s s u r e , e t c . Q u a n t i f i c a t i o n of d u r a t i o n i s more d i r e c t than that of fundamental frequency, however. The v a r i a b i l i t y i n i n t e n s i t y and frequency may be due to e f f e c t s of i n s t r u m e n t a l e r r o r . The most e x t e n s i v e s t u d i e s of the i n f a n t c r y have been conducted by Wasz-H8ckert et a l . (1968). Recordings were made of ' s i t u a t i o n a l ' c r i e s of normal i n f a n t s : the b i r t h c r y , hunger c r i e s ( p r e f e e d ) , p a i n c r i e s ( a f t e r p a i n f u l s t i m u l u s ) , and p l e a s u r e s i g n a l s (comfort s t a t e , i n f a n t h e l d ) . A n a l y s i s of the f o l l o w i n g a t t r i b u t e s of the c r i e s was made a c c o r d i n g to l e n g t h of main s i g n a l , minimum, mean, maximum p i t c h (10 Hz c r i t e r i o n f o r range), s h i f t of p i t c h (the presence or absence o f ) , v o i c i n g * , melody types ( r i s i n g - f a l l i n g , f a l l i n g , f l a t , r i s i n g , f a l l i n g - r i s i n g , w i t h a 10% change c r i t e r i o n d u r i n g IO70 of the c r y ) , c o n t i n u i t y of the s i g n a l ( 0 . 4 second minimum), g l o t t a l p l o s i v e s , v o c a l f r y * , n a s a l i t y * , tenseness*, subharmonic break* ( 1 9 6 8 , pp. 9 - l 4 . S t a r r e d a t t r i b u t e s were sampled but not a n a l y z e d , s i n c e they are d i f f i c u l t to see on the spectrograms.) These p a r t i c u l a r a t t r i b u t e s were chosen from those d i s c u s s e d by Jakobson, Fant, and H a l l e (1952). A summary of the d e f i n i t i v e f e a t u r e s of each c r y i s p resented i n Table 1.6. 46 I n s e r t Table 1.6 about here The e s t a b l i s h m e n t of c r y types by a c o u s t i c a t t r i b u t e s was supplemented by human a u d i t o r y i d e n t i f i c a t i o n t a s k s . I t was found t h a t those experienced i n h a n d l i n g i n f a n t s b e s t i d e n t -i f i e d the c r y types, p a r t i c u l a r l y the • t y p i c a l 1 c r i e s ( 1 9 6 8 , p. 2 9 ) . T h i s evidence permits the s u p p o s i t i o n that i n f a n t s can to a c e r t a i n extent communicate t h e i r needs through v a r i a t i o n of a c o u s t i c f e a t u r e s of t h e i r v o c a l i z a t i o n s . In a r e c e n t r e p o r t , Vuorenkoski et a l . (1971) d e s c r i b e d a r a t i n g scheme to d i s t i n g u i s h abnormal and normal i n f a n t s at b i r t h and s h o r t l y t h e r e a f t e r on the b a s i s of d i f f e r e n c e s i n the aforementioned a c o u s t i c c h a r a c t e r i s t i c s . Maximum p i t c h and b i - p h o n a t i o n (sound w i t h two harmonic sources) appeared to be the b e s t c r i t e r i a f o r d i s c r i m i n a t i o n between normal and abnormal i n f a n t s (p. 7 1 ) . M i c h e l s s o n ( 1 9 7 1 ) , i n a study of the v o c a l c h a r a c t e r i s t i c s of low b i r t h weight and as p h y x i a t e d neonates found t h a t , be-s i d e s maximum p i t c h and b i - p h o n a t i o n , l a t e n c y of c r y a f t e r p a i n s t i m u l u s , second pause ( i n a doubly phonated c r y ) , d u r a t i o n , minimum p i t c h , maximum p i t c h of s h i f t , melody type and ' g l i d i n g ' ( l a r g e q u i c k s h i f t ) , were a l s o u s e f u l c r i t e r i a f o r d i s t i n g -u i s h i n g h e a l t h y from unhealthy i n f a n t s . TABLE 1.6 ATTRIBUTES OF INFANT CRIES AS FOUND BY WASZ-HOCKERT ET AL. (1968) Attribute Birthcry Pain cry Hunger cry Pleasure cry Mean length 1 second Long but variable Voicing 60% = voiceless Voiced Melody type Flat or falling Falling Ris ing-f ailing Flat,rising-failing Tense or lax Tense Tense Lax Maximum pitch High High Lower than pain cry Pitch of shift In about 1/3 of cries Rare Rises and falls Subharmonic break 50% of cries Rare Vocal fry Rare Over 50% of cries Glottal plosives Rare Present Rare Nasality Present General pitch Variable Appearance Birth First few days First few days Three months Changes over time Increase in maximum pitch and duration More subharmonic breaks Fewer glottal plosives Increase in glottal plosives (Based on Wasz-Hockert et a l . , 1968, pp. 21-22) 48 These kinds of analyses p r o v i d e a more p r e c i s e measure than has p r e v i o u s l y been obtained i n the study of v o c a l c h a r a c t e r i s t i c s of neonates. In order to be c l i n i c a l l y v a l i d , they may need more e x t e n s i v e s t a n d a r d i z a t i o n on normal i n f a n t s . While most a c o u s t i c a n a l y s e s of v o c a l development have been made on the sound sp e c t r o g r a p h , Sheppard and Lane (1968) attempted, 'without r e s o l v i n g the q u e s t i o n of the v a l i d i t y of s p e c t r o g r a p h s d e s c r i p t i o n ' , to develop a new method of a n a l y s i s u s i n g an a n a l o g - t o - d i g i t a l c o n v e r t e r and d i g i t a l computer (p. 97). V o i c e - a c t i v a t e d microphones were used to make tape r e c o r d i n g s of the v o c a l i z a t i o n s of two i n f a n t s up to f i v e months of age. To reduce the noise l e v e l on the tapes, the c h i l d r e n were kept i n p l e x i g l a s s c r i b s . P e r t i n e n t obser-v a t i o n s of the s i t u a t i o n were made by the p a r e n t s . From the voluminous amount of data c o l l e c t e d , three 95 second samples (the f i r s t 95 seconds of each fou r - h o u r r e c o r d i n g b l o c k ) were chosen from every f o u r t h day of r e c o r d i n g . In a n a l y s i s , the s i g n a l s were sampled every 25 msec by the A/D-converter to e x t r a c t the fundamental frequency, the d u r a t i o n , and the amplitude of each u t t e r a n c e . To o b t a i n the b e s t estimate of fundamental frequency, the s i g n a l was f i l t e r e d i n t o two ranges by f r e q u e n c y . D u r a t i o n was c o r r e l a t e d w i t h amplitude to d e f i n e the b e g i n n i n g and the end of u t t e r a n c e ( i . e . , a t h r e s h o l d value of a m p l i t u d e ) . The temporal t h r e s h o l d chosen was 100 msec, s i n c e , t h i s v a l u e appeared to be a minimum f o r d u r a t i o n . 49 In s t a t i s t i c a l a n a l y s i s , the number, d u r a t i o n , and mean fund-amental frequency and amplitude of each u t t e r a n c e was d e t e r -mined. The s t a t i s t i c s were then pooled, and frequency d i s t -r i b u t i o n s over the e n t i r e sample were c a l c u l a t e d by the computer. Two s t a t i s t i c s were then r e p o r t e d : w i t h i n - u t t e r -ance measures of c e n t r a l tendency and v a r i a b i l i t y , and between-u t t e r a n c e measures of c e n t r a l tendency and v a r i a b i l i t y . The r e s u l t s were as f o l l o w s : (1) For d u r a t i o n , the geometric mean had to be c a l c u l a t e d , s i n c e there was a r i g h t skewing of the d a t a . The c o e f -f i c i e n t of v a r i a t i o n decreased over time ( c f . Table k.l), (2) The c o e f f i c i e n t of v a r i a t i o n was g r e a t e r f o r amplitude than f o r frequency. For n e i t h e r , d i d i t change s i g n i f -i c a n t l y over time. (3) The means of frequency f i r s t decreased, then i n c r e a s e d and s t a b i l i z e d ( c f . Table k.l). T h i s t r e n d w i t h r e s p e c t to frequency c o r r e l a t e d w i t h that o b t a i n e d by Fairbanks (19^2), who, i n h i s s i n g l e - c h i l d study of hunger w a i l s , a l s o noted an i n i t i a l decrease i n fundamental frequency f o l l o w e d by an i n c r e a s e . In a g e n e r a l c r i t i c i s m of Sheppard and Lane's work, i t can be s a i d t h a t they have minimized the c a l c u l a t i o n e r r o r by u s i n g the computer to e x t r a c t i n f o r m a t i o n . The number of p o i n t s that are sampled i n computer a n a l y s i s i n c r e a s e s the v a l i d i t y of the r e s u l t s . However, there are f a c t o r s i n the 50 pre-computer data c o l l e c t i o n which could have decreased the v a l i d i t y of t h e i r results as normative data. F i r s t , the number of subjects i s i n s i g n i f i c a n t . Secondly, the ch i l d r e n were not i n a completely natural environment, and hence, t h e i r reactions cannot be assumed to be exactly equivalent to those of c h i l d r e n i n the i r natural environments. The method of utterance s e l e c t i o n was consistent but only representative of the c h i l d ' s i n i t i a l vocal behaviour i n any four-hour block of time. In t h e i r data, no d i s t i n c t i o n could be made between crying and non-crying utterances, which have been described as perceptually and a c o u s t i c a l l y d i f f e r e n t (cf. Murai, i960, 1963; Lenneberg, 1967» p. 276). This resulted i n an averaging of longer and higher-pitched c r i e s and shorter lower-pitched non-crying utterances, and may have affected the trends found. In t h e i r discussion they postulated that the p h y s i o l o g i c a l l y based high-pitched cry of the f i r s t few weeks stops, lower-pitched sounds begin, and then a second form of 'operant* cry is i n i t i a t e d (p. 106). To test this hypothesis, a separate study of c r i e s and non-cries would have to be made. Up to this point, a l l studies have either only been i n c i -d entally concerned with the vocal interactions of the infant with his environment, or have not included i t at a l l . In the review of general developmental studies, i t was emphasized 51 t h a t the i n t e r a c t i o n s of an i n d i v i d u a l w i t h h i s environment were a t a r g e t area f o r the study of development, s i n c e an i n d i v i d u a l does not grow i n vacuo. S e v e r a l e x p e r i m e n t a l l y c o n t r o l l e d s t u d i e s of the e f f e c t of environmental v a r i a b l e s on v o c a l development are d e s c r i b e d i n the f o l l o w i n g s e c t i o n . 1 . 2 2 3 . S t u d i e s of the i n f l u e n c e of e x t r a l i n g u i s t i c f a c t o r s  on v o c a l development. As was the case f o r s t u d i e s of g e n e r a l development, a t o p i c of major i n t e r e s t f o r those examining the i n f l u e n c e of environmental v a r i a b l e s on development i s the e f f e c t of stimu-l a t i o n and/or d e p r i v a t i o n . In s t u d i e s of v o c a l development d u r i n g the f i r s t year of l i f e , the e f f e c t of the presence of an a d u l t on the amount of v o c a l i z a t i o n , one example of t h i s k i n d of r e s e a r c h , i s f r e q u e n t l y examined. In a simple s o c i a l r e i n f o r c e m e n t paradigm, Rheingold (1959) s t u d i e d the amount of v o c a l i z a t i o n o f i n f a n t s (median age; 3 months) i n three 9-minute p e r i o d s f o r s i x days. On the f i r s t two days, a b a s e l i n e count was made. On the f o l l o w i n g two days, reinforcement was g i v e n a f t e r each v o c a l i z a t i o n (a s m i l e , three " t s k ' s " . and a l i g h t t o u c h ) . Reinforcement was not g i v e n on the l a s t two days. The r e s u l t s were as a n t i c -i p a t e d ! the reinforcement i n c r e a s e d the amount of v o c a l i z a t i o n and the withdrawal of rei n f o r c e m e n t then reduced i t a g a i n . 52 To examine t h i s t r e n d more c l o s e l y , tfeisberg (1963) t e s t e d s i x groups of i n f a n t s ( a l s o 3 months of age) over an 8-day p e r i o d . The groups were c a t e g o r i z e d a c c o r d i n g to the f o l l o w i n g c o n d i t i o n s : (1) no experimenter pr e s e n t ; (2) experimenter present but w i t h an e x p r e s s i o n l e s s f a c e ; (3) noncontigent s o c i a l s t i m u l a t i o n ; (k) noncontingent n o n s o c i a l but a d d i t o r y s t i m u l a t i o n , experimenter present, but w i t h an e x p r e s s i o n l e s s f a c e ; (5) s o c i a l s t i m u l a t i o n c o n t i g e n t upon v o c a l i z a t i o n ; and (6) n o n s o c i a l a u d i t o r y s t i m u l a t i o n c o n t i g e n t upon v o c a l i z -a t i o n , experimenter p r e s e n t , w i t h an e x p r e s s i o n l e s s f a c e . Only f o r the f i f t h group was there a s i g n i f i c a n t i n c r e a s e of v o c a l i z a t i o n . Once again , the t r e n d to e f f e c t i v e i n c r e a s e i n v o c a l i z a t i o n through s o c i a l r e i n f o r c e m e n t was noted. There were m i s s i n g c o n d i t i o n s , i . e . , c o n t i g e n t and noncontingent n o n s o c i a l s t i m u l a t i o n w i t h experimenter absent. The i n c l u -s i o n of these c o n d i t i o n s would have p r o v i d e d more i n f o r m a t i o n about the d i f f e r e n c e s between s o c i a l and n o n s o c i a l s t i m u l a t i o n . Todd and Palmer ( 1968) s t u d i e d the l a t t e r problem s p e c i f -i c a l l y . An i n s t r u m e n t a l c o n d i t i o n i n g of b a b b l i n g under s o c i a l a u d i t o r y reinforcement (tape r e c o r d i n g of a v o i c e ) was implem-ented on s i x t e e n i n f a n t s w i t h a mean age of 85 days. I t was noted that there was a g r e a t e r i n c r e a s e i n v o c a l i z a t i o n i f an a d u l t was present d u r i n g the time of r e i n f o r c e m e n t . T h i s may i n d i c a t e that v i s u a l r e i n f o r c e m e n t may be important i n the 53 augmentation of the amount of v o c a l i z a t i o n , p a r t i c u l a r l y i n the f i r s t few months of l i f e , when, a c c o r d i n g to White (1971), i n f a n t s are a p p a r e n t l y • v i s u a l - p r e h e n s o r y c r e a t u r e s ' (p. 5 2 ) • T h i s experimental study c o r r e l a t e d g e n e r a l l y w i t h Nakazima's o b s e r v a t i o n that some of the c h i l d r e n appeared to v o c a l i z e more i n the presence of an a d u l t . He noted, however, that t h i s was not t r u e f o r a l l of h i s s u b j e c t s . A study w i t h s i m i l a r s t i m u l i , but w i t h the o b j e c t i v e of c o r r e l a t i n g body a c t i v i t y l e v e l to a u d i t o r y s t i m u l i , was c a r r i e d out by Turnure (1971). C h i l d r e n from three age-groups (3 months, 6 months, and 9 months) were presented w i t h tape-reco r d e d s t i m u l i : the monther's normal v o i c e , the mother's s l i g h t l y d i s t o r t e d v o i c e , the mother's g r o s s l y d i s t o r t e d v o i c e , and a female s t r a n g e r ' s v o i c e . The index of response was body a c t i v i t y ( i . e . , s m i l e s , frowns, c r i e s , mouthing n o n - c r i e s , limb-mouth c o n t a c t ) . With the p r e s e n t a t i o n of a l l v e r s i o n s of the s t i m u l i , there was g e n e r a l motor q u i e t i n g . The 3-month group showed more mouthing to the s t r a n g e r ' s v o i c e and the 6-month group, more c r y i n g i n response to the mother's v o i c e . T h i s study i n d i c a t e s that a t t e n t i o n to a s t i m u l u s tends to decrease motor a c t i v i t y , i n some ways thus c o n t r a d i c t i n g e v i d -ence t h a t a c h i l d v o c a l i z e s more i n the presence of s t i m u l a t i o n . However, i n the 6-month-old group, there was c r y i n g noted i n response to the mother's v o i c e . The reason f o r the e l i c i t a t i o n 54 of a cry rather than a non-cry i s unclear. It i s also i n t e r -esting that d i s t o r t i o n of the stimulus did not a f f e c t the response. Jones and Moss (1971) conducted a study to 'further d i f f e r e n t i a t e the status of environmental and organismic factors as they relate to vocal behaviour i n a n a t u r a l i s t i c s e t t i n g ' i n the f i r s t three months of l i f e (p. 1 0 3 9 ) . Continuous, 3-hour recordings of mother-infant behavior were made i n the homes of 14- female and 14- male infants on 2 days when the infants were about 2 weeks old and on 2 days when the infants were about 3 months old. ( 1 9 7 1 , p. 1039) S t a t i s t i c a l analyses of the interactions of age, state (active awake, passive awake, drowsy, active sleep, and passive sleep), maternal presence, maternal speech, and se were made. Results indicated that a l l c h i l d r e n vocalized most when i n the active awake state, the c h i l d r e n v o c a l i z i n g more when 3 months of age. It appeared that the r e l a t i o n between the mother's presence or speech and the i n ants' vocalizations was age- and state-dependent: ( 1 ) 'at 2 weeks, the amount of v o c a l i z a t i o n was p o s i t i v e l y related to the amount of the mother's speech that followed the infant's v o c a l i z a t i o n s ' (p. 1 0 3 9 ) ; (2 ) 'at 3 months, the amount of v o c a l i z a t i o n was p o s i t i v e l y related to the amount of mother's speech that followed the infant's v o c a l i z a t i o n s ' (p. 1 0 3 9 ) ; and ( 3 ) the c h i l d r e n vocalized less i n the active awake state than i n the passive awake state when 55 the mother was present (p. lOkk). It was i n c i d e n t a l l y noted that, at least i n the case of the e a r l i e r period, the most talk a t i v e mothers had the least vocal c h i l d r e n (p. 1048). No sex differences were noted. The authors presented various hypotheses to account for t h e i r r e s u l t s . They do not deduce that there i s a necessary cause-effect r e l a t i o n s h i p between maternal behaviour and infant v o c a l i z a t i o n , but rather that there i s an associative e f f e c t which may be b i d i r e c t i o n a l (p. 1048). It was further hypothesized that the difference between the ages with respect to the e f f e c t of maternal be-haviour may be a residual of the mere increase i n v o c a l i z a t i o n at 3 months, i . e . , the i n f a n t s ' speech becomes less of a novel stimulus to the mothers and therefore reduces the amount of i n t e r a c t i o n between them. From this study, i t can be seen that early vocal behaviour i s not necessarily s o c i a l l y oriented. However$ the authors point out that, since vocalizations are more frequent i n the active awake state, they are at least a v a i l a b l e f o r s o c i a l situations (p. 1 0 5 0 ) . Why the mothers had less e f f e c t than anticipated could have been because a human being induces other than vocal responses (cf. Turnure, 1971» above), and/or because the mother, being a f a m i l i a r •object' does not have the effect of novelty to evoke a response (p. 1 0 5 0 ) . The above studies are i n f a c t s t i l l exploratory, although they do show a trend of infant reaction by a behavioural response i . e . , an increase or decrease i n v o c a l i z a t i o n , to eftviroamental 56 s t i m u l a t i o n . As was d i s c u s s e d i n the s e c t i o n on s t u d i e s of i n f a n t p e r c e p t i o n , there are many f a c e t s of r e s e a r c h which attempts to r e l a t e stimulus to response s t i l l to be v a l i d a t e d , however. The e f f e c t of the s o c i a l environment on a s p e c i f i c a l l y a c o u s t i c f e a t u r e of v o c a l i z a t i o n has been mentioned by Lieberman (19^7 )• I t appeared that two c h i l d r e n of 10 and 13 months (one male, one female) a d j u s t e d t h e i r fundamental f r e -quency to resemble more c l o s e l y t h a t of t h e i r f a t h e r or mother, when they were producing n o n - c r y i n g u t t e r a n c e s ( c f . Table 1 . 7 ) . I n s e r t Table 1.7 about here T h i s i m p l i e s g e n e r a l l y t h a t : ( 1 ) s o c i a l environment i s i n f l u e n t i a l i n the c h i l d ' s v o c a l development at the end of the f i r s t year and ( 2 ) a u d i t o r y p e r c e p t i o n may i n f l u e n c e v o c a l i c p r o d u c t i o n on a suprasegraental l e v e l , i . e . i m i t a t i o n may occur on a suprasegmental l e v e l . Lieberman u n f o r t u n a t e l y n e i t h e r i n c l u d e s an o u t l i n e of h i s methodology nor a more e x p l i c i t r e f e r e n c e f o r t h i s r e s e a r c h . His sample of 2 i s i n s i g n i f i c a n t , however. Kaplan (1970) r e p o r t e d i n c i d e n t a l l y i n a study of percep-t i o n of i n t o n a t i o n a l contours by k- and 8-raonth-old i n f a n t s , t h a t 4-month-old i n f a n t s demonstrated v a r i a b i l i t y i n heart • 57 TABLE 1.7 -AVERAGE FUNDAMENTAL FREQUENCY OF CHILDREN'S BABBLING AND SPEECH VERSUS AVERAGE FUNDAMENTAL FREQUENCY OF CHILDREN'S CRYING Utterance Subj ect Condition Speech Crying 10-month.rold boy Alone in crib 430 Hz 550 Hz Playing with father 340 Hz 500 Hz Playing with mother 390 Hz 420 Hz 13-month-old girl Playing with father 290 Hz 450 Hz Playing with mother 390 Hz 450 Hz (Based on Lieberman, 1967, p. 46) 58 rate when a switch from a male voice stimulus to a female voice stimulus was made. This was considered a p o s i t i v e reaction to the difference between the two voices (p. 10). It was also found that 8-month-old infants could apparently discriminate f a l l i n g and r i s i n g contours, including the stress marker. These purely perceptual r e s u l t s further support the hypothesis that suprasegmentals are perceived at an early age. 59 1,3. Summary and statement of the problem From a review of the l i t e r a t u r e on c h i l d development, i n p a r t i c u l a r , vocal development, i t appears that most aspects of the subject are as yet t h e o r e t i c a l l y u n c l a r i f i e d . Valid theories depend on r e l i a b l e empirical investigations, of which there have been few i n this area. The primary need i s then the c o l l e c t i o n and analysis of empirical data. With s p e c i f i c regard to l i n g u i s t i c development, i t ap-pears that a study of vocal behaviour i n the f i r s t year of l i f e has relevance f o r the study of language development as a whole. In his f i r s t year of l i f e , the c h i l d has not yet learned to communicate with the a r b i t r a r y segmental code of his l i n g -u i s t i c environment. Nevertheless, he can apparently communicate c e r t a i n desires, and needs, through variations of the basic acoustic features of his vocal signal -- duration, fundamental frequency, and i n t e n s i t y . With the advanced techniques of data analysis, i t i s possible to study more pr e c i s e l y the acoustic features of sound production. Some acoustic studies have been made of a l l infant vocalizations, some of the c r i e s only. Since c r i e s and non-cries may have d i f f e r e n t developmental trends (cf. Lenneberg, 1967; -Murai, 1963), a separate analysis i s warranted. A longitudinal study of the development of the non-crying utterances only may help to c l a r i f y the question of speech sound development, since a speech sound i s i t s e l f usually 60 a non-cry. From the a c o u s t i c study of the i n f a n t ' s non-cry u t t e r a n c e s , t h e n , may be d e r i v e d both s y n c h r o n i c and d i a c h r o n i c i n f o r m a t i o n about v o c a l development. Synchronic i n f o r m a t i o n may e v e n t u a l l y p r o v i d e norms of v o c a l development; d i a c h r o n i c i n f o r m a t i o n may giv e n i n s i g h t i n t o the g r a d u a l emergence of language, the complex segmental-suprasegmental code which i s b u i l t upon the framework p r o v i d e d by the s i m p l e r and e a r l i e r method of communication. In c o l l e c t i o n of t h i s data, two s e t t i n g s can be envisaged: the l a b o r a t o r y or the home environment. The l a b o r a t o r y o f f e r s p o s i t i v e c o n d i t i o n s f o r tape r e c o r d i n g and v a r i o u s c o n t r o l purposes. However, i t i s c l e a r from a review of the l i t e r a t u r e t h a t the c h i l d ' s development i s i n e x t r i c a b l y i n t e r t w i n e d w i t h h i s i n t e r a c t i o n s i n h i s home environment. C o l l e c t i o n of data i n h i s home environment w i l l o f f e r normal c o n d i t i o n s to the i n f a n t and thereby i n c r e a s e the p r o b a b i l i t y of normal spontan-e i t y of v o c a l i z a t i o n . From the p o i n t s of view mentioned above, developed the o b j e c t i v e s of the presen t study: to r e c o r d v o c a l development i n the f i r s t f o u r months of l i f e of s e v e r a l c h i l d r e n i n t h e i r home environments; to analyse a c o u s t i c a l l y n o n - c r y i n g u t t e r -ances w i t h a view to f o l l o w the development of a c o u s t i c f e a -t u r e s and to r e l a t e the c h i l d ' s i n t e r a c t i o n w i t h h i s e n v i r o n -ment to h i s v o c a l behaviour i n bot h a q u a l i t a t i v e and q u a n t i -t a t i v e manner. CHAPTER 2 Method 2.1. Experimental Design The present study r e p r e s e n t s the i n i t i a l phase of a l a r g e r i n v e s t i g a t i o n on the e v o l u t i o n of i n f a n t speech sound p r o d u c t i o n d u r i n g the f i r s t two years of l i f e . The f i r s t s i x i n f a n t s (three males and three females, d e s c r i b e d i n more d e t a i l i n S e c t i o n 2.2) from the l a r g e r sample of 18 normal, f i r s t b o r n , f u l l - t e r m i n f a n t s , r e p r e s e n t a t i v e of l o c a l p o p u l -a t i o n c h a r a c t e r i s t i c s , served as s u b j e c t s . The spontaneous v o c a l i z a t i o n s of these i n f a n t s i n i n t e r -a c t i o n w i t h t h e i r f a m i l i a l environment are c o l l e c t e d by means of 15-minute magnetic tape r e c o r d i n g s , b e g i n n i n g at 5 weeks of age and p r o c e e d i n g on a biweekly b a s i s — i n t h i s study, up to l 6 weeks of age f o r f i v e of the s u b j e c t and up to 22 weeks of age f o r one s u b j e c t . In a d d i t i o n to the r e c o r d i n g s e s s i o n , b i o g r a p h i c a l data on the i n f a n t i s c o l l e c t e d a t each v i s i t ; c u r r e n t h e a l t h s t a t u s , r e a c t i o n s to v a c c i n a t i o n s , p a r e n t a l o b s e r v a t i o n s of the c h i l d ' s behaviour e t c . To p r o v i d e a more o b j e c t i v e a p p r a i s a l of the c h i l d ' s development, a p s y c h o l o g i s t admin-i s t e r s the Bayley Scales of I n f a n t Development (1969) every three months, b e g i n n i n g at the age of three months. Informa-61 62 t i o n on the home environment i s b e i n g o b t a i n e d and ev a l u a t e d by means of the Heiraler S c a l e of S o c i a l F u n c t i o n i n g ( 1 9 6 7 ) , a d m i n i s t e r e d by E every f o u r months, the f i r s t t e s t b e i n g a d m i n i s t e r e d around the time of the b i r t h of the c h i l d . Such i n f o r m a t i o n p r o v i d e s a d d i t i o n a l measures f o r e s t a b l i s h i n g i n t e r s u b j e c t c o m p a r a b i l i t y . Due to the f a c t t h a t , i n the present study, there are seldom more than one or two s e t s of value s f o r , these t e s t s , developmental and s o c i a l data are used o n l y d e s c r i p t i v e l y to suggest reasons f o r d i f f e r e n c e s among c h i l d r e n a c c o r d i n g to c h r o n o l o g i c a l age. Consequently, c h r o n o l o g i c a l age i s , f o r the present study, the main c r i t e r i o n f o r s t a t i s t i c a l a n a l y s i s . In the l a r g e r study, a l l speech samples are b e i n g sub-j e c t e d to p e r c e p t u a l and i n s t r u m e n t a l a n a l y s i s , the l a t t e r p r i m a r i l y by means of the sound s p e c t r o g r a p h . In t h i s i n i t i a l study, the a c o u s t i c f e a t u r e s of fundamental frequency and dura-t i o n are i n v e s t i g a t e d by means of s p e c t r o g r a p h i c a n a l y s i s . These f e a t u r e s are submitted to s t a t i s t i c a l a n a l y s i s by com-puter i n the f o l l o w i n g way: w i t h i n each t a p i n g s e s s i o n f o r each c h i l d , between s e s s i o n s f o r each c h i l d , and a c r o s s c h i l d -ren (where s t a t i s t i c a l l y f e a s i b l e ) . Furthermore, i n order to examine the p o s s i b l e e f f e c t of the c h i l d ' s i n t e r a c t i o n w i t h h i s environment upon h i s v o c a l development, the u t t e r a n c e s 63 are c l a s s i f i e d a c c o r d i n g to s i t u a t i o n and a n a l y z e d f o r f und-amental frequency w i t h a view to comparing the d i f f e r i n g c o n t e x t s . 2 . 2 . S u b j e c t s 2 . 2 1 . Sex and age Three male and two female i n f a n t s were s t u d i e d from 5 -16 weeks; one female i n f a n t (CAB) was s t u d i e d from 5 - 2 2 weeks. 2 . 2 2 . M e d i c a l h i s t o r y The mothers of the i n f a n t s were r e f e r r e d to E_ by l o c a l o b s t e t r i c i a n s and p a e d i a t r i c i a n s on the b a s i s of uncomplicated pregnancy and no h i s t o r y of gross p h y s i c a l or p s y c h o l o g i c a l d i s o r d e r s . Although the mothers of AMG and DAE had had p r e -v i o u s pregnancies, the i n f a n t s were n e v e r t h e l e s s the o n l y c h i l d r e n thus f a r i n the f a m i l y . P e r i n a t a l h i s t o r i e s of the i n f a n t s i n d i c a t e d t h a t a l l were m e d i c a l l y sound ( c f . Table 2 . 1 f o r p e r i n a t a l d e t a i l s ) . For AMG, no Apgar r a t i n g I n s e r t Table 2 . 1 about here was a v a i l a b l e , s i n c e she was born spontaneously at home; TABLE 2.1 MEDICAL HISTORY OF INFANTS Child CAB. AMG AMR JLR DAE MJK Sex Female Female Male Female Male Male Eirthdate (Day/month/year) 6/7/71 27/9/71 5/12/71 14/10/71 3/12/71 13/11/71 Birthweight (gms) 3800 3100 3600 3510 3790 4220 Apgar score" 10 — 9 2 7/9 8/10 5 8 Labour (hrs: min.) 11:45 4:50 8:06 19:55 5:31 Blood type B, Rh- A, Rh+ 0, Rh+ 0, Rh+ A, Rh+ . B, Rh+ Maternal weight gain (lbs) 18 20 8 30 28 40 Intended feeding method upon discharge from hospital Formula Formula Breast Breast Breast Breast * Recorded at one minute after birth; i f second Apgar score i s given, the superscript indicates time of determination i n minutes after birth. 6 5 however, upon a r r i v a l a t h o s p i t a l , she was c l a s s i f i e d as a normal, h e a l t h y baby. In s p i t e of prolonged l a b o u r w i t h f o e t a l d i s t r e s s noted f o r DAE, the Apgar r a t i n g i n d i c a t e d h e a l t h y postpartum s t a t u s . Subsequent m e d i c a l and p a r e n t a l r e p o r t s have i n d i c a t e d t h a t , f o r the d u r a t i o n of the present study, the c h i l d r e n c o n t i n u e d to be normal and h e a l t h y . 2 . 2 3 . P s y c h o l o g i c a l development A d m i n i s t r a t i o n of the r e v i s e d B a y l e y S c a l e s of I n f a n t Development (Bayley, 1969) p r o v i d e d a measure of the i n f a n t s * psychomotor and mental development. R e s u l t s are t a b u l a t e d i n Table 2 . 2 . I n s e r t Table 2 . 2 about h e r e . From t h i s t a b l e , d i f f e r e n c e s can be noted among c h i l d r e n . At 3 months, AMR, CAB, and DAE e x h i b i t e d a s l i g h t d elay psychomotor development, CAB a l s o e v i n c i n g some d e l a y i n mental development. At 6 months, AMG- and CAB showed slowness i n mental development. The only i n f a n t who demonstrated super-i o r i t y on b o t h i n d i c e s was JLR, who at 3 . 5 months performed at the 5-month l e v e l f o r PDI and at the l*-month l e v e l f o r MDI. 66 TABLE 2.2 RESULTS OF BAYLEY TESTS OF INFANT DEVELOPMENT: MDI/PDIa S Age level i n months at test administration 3 3.5 5.5 6 CAB 72/80 > • 69/112b (2~/2) (4.5/7) AMG 88/94 82/100b (2.5/3") (5 +/6) AMR 91/80 — _ 85/104b (2.5+/2) (5.5/6) JLR 114/131b 85/99 (4/5) (5/5.5) DAE 94/80 82/96 (3"/2) (5.5"/6~) MJK 92/90 94/114b (3/3) (5 +/6) a Standard scores with Mean =100 and SD =16: MDI = Mental Development Index, and PDI = Psychomotor Development Index. Parenthetic notation indicates age-level equivalents ( i n months) based on raw scores. Difference between MDI and PDI i s significant (p_< .05); i . e . , median significant difference at this level i s 16.7 points (cf. Bayley, 1969, pp. 18-19). 67 The Infant Behaviour Record, a more subjective evaluation of the infant's development, was also administered at three months to a l l Ss but CAB (due to an oversight). A l l infants appeared normally responsive and attentive, whereby JLR and MJK were somewhat more so than the others. At six months, CAB also appeared normally a l e r t and responsive. 2 . 2 4 . F a m i l i a l environment and biographical information The f a m i l i e s chosen were considered to be l o c a l l y representative by SES group, education, i n t e r e s t s , s o c i a l outlook, etc. Language, Education, SES status Parents are native speakers of English. A l l are Canadian but DAE's father, who i s from Manchester. In 1970, the average income of these f a m i l i e s was $10,000 (range from $6,000 - $13,000). In the case of the mothers, occupation l i s t e d i s that p r i o r to the b i r t h of the c h i l d . No parent has had less than eleven years of schooling and t r a i n i n g . In several cases, there has been post-high school education; only JLR's father has a uni v e r s i t y degree (cf. Table 2.3). Insert Table 2.3 about here 68 TABLE 2.3 EDUCATION, OCCUPATION AND INCOME OF FAMILIES Parent Education (in years) Public school/ Vocational University Occupation Approximate family income CAB Father 13/4/0 Tool and diemaker $10,000. Mother 11/2/0 Practical nurse AMG Father 14/0 1 Insurance inspector $13,000. Mother 13/1/0 Departmental manager in store AMR Father 13/1/0 Warehouseman $13,000. Mother 12/0/0 Secretary JLR Father 12/0/7 Ph.D. candidate $8,000. Mother 12/0/1 Secretary DAE Father 12/0/1 Firefighter $10,000. Mother 10/0/1 Secretary MJK Father 11/0/0 Bandsaw operator $6,000. Mother 12/0/2 Secretary 69 Other b i o g r a p h i c a l i n f o r m a t i o n The median age of the parents i s 25 years (range 2 3 - 3 3 ) . In the f a m i l i e s of CAB, AMG and DAE, the c h i l d was born i n the f i r s t y ear of marriage, whereas i n the other three fam-i l i e s , the b i r t h of the c h i l d o c c u r r e d a t l e a s t t hree years a f t e r marriage. The r e a d i n g i n t e r e s t s and hobbies are i n c l -uded as a p o s s i b l e i n d i c a t i o n of the i n t e l l e c t u a l / c r e a t i v e d i s p o s i t i o n of the f a m i l i e s . Noteworthy r e a d i n g i n t e r e s t s are e v i d e n t i n JLR*s and JIJK's homes. In these homes, as w e l l as i n AMR's there a l s o i s a d i s p o s i t i o n toward c r e a t i v e hobbies, ( c f . Table 2.4.) I n s e r t Table 2.4 about here . A s t a n d a r d i z e d a p p r a i s a l of the s o c i o - p s y c h o l o g i c a l s t a b i l i t y w i t h i n the home environment was p r o v i d e d by the Heimler S c a l e of S o c i a l F u n c t i o n i n g (Rev. I I ) and i n d i c a t e d t h a t , a t the times of a d m i n i s t r a t i o n , a l l parents had g e n e r a l l y normal a t t i t u d e s toward t h e i r l i f e s i t u a t i o n s ( c f . Table 2 . 5 . , where: P o s i t i v e Index Score = degree of s a t i s f a c t i o n i n f i v e areas — w o r k / a c t i v i t y , f i n a n c e , f r i e n d h s i p , f a m i l y , p e r s o n a l ; Negative Index Score = degree of f r u s t r a t i o n / d i s s a t i s f a c t i o n i n l i f e i n f i v e main areas — n o n - a c t i v i t y , somatic, p e r s e c u t i o n , depress-i o n , escape routes; S y n t h e s i s Score = g e n e r a l o u t l o o k on l i f e ) . 70 TABLE 2.4 PARENTS: BIOGRAPHICAL INFORMATION Parent Age Reading Interests Hobbies CAB Earner Mother AMG Father Mother AMR Father Mother JLR Father Mother DAE Father Mother MJK Father Mother 33 26 24 24 29 28 25 25 27 28 23 24 Historical biography; boating Photography, camping, boat and garden magazines, Playboy building Biography, women's magazines, Sewing, knitting, entertaining Playboy Historical fiction, adventure Spectator sports, parlor games stories Historical fiction, Book-of- Knitting, sewing, cooking, the Month club, magazines golf Time, Playboy, fiction Reader's Digest, Time Science fiction, general fiction, biography, Book-of the-Month club Non-fiction and fiction, child development Golf, skiing, drafting design Eowling, swimming, oil paintings tennis Painting, golf, floor hockey Involves self in husband's in-terests - no singular interests Historical fiction, Playboy Spectator sports, golf, movie photography Modern novels, women's mag- Sewing,•cooking, crocheting azines and Playboy Playboy and general interest Bric-a-brac collection, tennis magazines, yoga and psychology books Classics and general fiction, Arts and crafts, attends opera monthly magazines and theatre, plays clarinet and guitar 71 i n s e r t Table 2.5. about here Parent-child i n t e r a c t i o n E noted that a l l parents except those of CAB appear to provide much stimulation for th e i r c h i l d r e n i n the form of a f f e c t i o n , conversation, and c o l o r f u l toys. In the families of AMG, AMR, and MJK, the mother i s more instrumental i n providing this stimulation, although the fathers are also interested. Less stimulation was given CAB by her parents at the time of this study; they expressed anxiety about 'spo i l i n g * the c h i l d with too much attention. Certain aspects of the physical home environment There i s some v a r i a b i l i t y i n the decor of the homes. Those of JLR and MJK are abundant i n v i s u a l l y and t a c t f u l l y stimulating objects, while that of CAB was somewhat lacking i n this respect (cf. Table 2.6). Descriptions i n the table r e f e r to room(s) i n which the infants spent the major part of waking hours, as well as general ambience. Insert Table 2.6. about here 72 TABLE 2.5 MEAN SCORES FOR PARENTS ON HEIMLER SCALE OF SOCIAL FUNCTIONING (REV. II) Infant Adniinistra-tion Date (in weeks after birth) Pos. Father Neg. Syn. Pos. Mother Neg. Syn. CAB (1) + 4 89 10 69 81 8 90 (2) + 16 89 8 76 74 8 82 (3) + 33 88 11 84 72 11 64 AMG (1) - 6 67 5 68 97 4 82 (2) + 14 78 9 66 97 9 86 (3) + 31 80 10 62 77 4 84 AMR (1) — 11 96 8 50 92 16 80 (2) + 20 100 6 72 92 16 88 JLR (1) - 2 90 27 84 89 13 76 (2) + 20 90 30 78 77 16 72 DAE (1) - 6 97 11 86 94 23 86 (2) + 21 90 17 92 68 11 94 MJK (1) + 22 70 5 80 96 9 70 (2) + 22 81 5 80 72 32 66 i Note. — Negative values in second column indicate that Heimler Scales were administered before the birth of the child. 73 TABLE 2.6 PHYSICAL ENVIRONMENT Subject Ambient noise Other CAB Other apartments, stereo Small; mute colors AMG Other apartments, radio, television Basement suite, l i v i n g room cool and dimly l i t although kitchen warm and bright; AMG usually in kitchen AMR Generally quiet; radio, stereo, television. Brightly colored JLR Traffic noise, radio, tape recorder, television Extensive visual and ta c t i l e stimulation DAE Construction noise, radio, television, stereo. Two cats MJK Generally quiet; radio, stereo, television Three cats, one dog, extensive visual stimulation 74 2 . 3• Proc edure 2 . 3 1 . Data c o l l e c t i o n 2 . 3 1 1 . Instrumentation Tape recordings were made on a Nagra IV-D portable tape recorder using an AKG D202E microphone and A mpex kjk Low-Noise tape. The tape recorder was ca l i b r a t e d to give a f l a t f r e -quency response (+2 dB) over the range 5 0 - 1 0 , 0 0 0 Hz. The d i r e c t i o n a l microphone was normally placed about t h i r t y - s i x inches from the infant's mouth. 2 . 3 1 2 . General taping s i t u a t i o n At each biweekly session, E c o l l e c t e d about f i f t e e n minutes of taperecorded utterances. These f i f t e e n minutes did not necessarily represent f i f t e e n consective minutes, f o r the tape recorder was often deactivated to exclude, f o r example, c r i e s , hiccups, sleep periods, and excessively noisy s i t u a t i o n . In order to obtain as much data as possible, the mothers were consulted as to the inf a n t s ' most active periods; the attempt was made to schedule sessions at such times. In addition, every attempt was made to preserve the natural home environment. Parents were encouraged to behave i n th e i r accustomed manner towards the c h i l d . If possible, both parents were present; but as a rule, only the mother was at home during the ch i l d ' s 75 active periods. Et with the tape recorder and microphone, remained out of the v i s u a l range of the c h i l d for the most of the taping sessions. The only a l t e r a t i o n of the environ-ment was to reduce the ambient noise to ensure c l a r i t y of recording by turning off radios, t e l e v i s i o n s , etc.; recording was accomplished i n the least noisy room of the house. 2 . 3 1 3 . S p e c i f i c taping s i t u a t i o n A record of information relevant to each taping s i t u a -tion was kept by E. This data i s presented i n Tables 2 . 7 - 2 . 1 2 . Insert Tables 2 . 7 - 2 .12 about here 2 . 3 2 . Spectrographic analysis 2 . 3 2 1 . Instrumentation The tapes c o l l e c t e d were reproduced on an Ampex kkOB tape recorder, c a l i b r a t e d within +2 dB of the Nagra IV-D tape record-er (over a 50-10,000 Hz range). A Kay-Sonagraph, Model 7029A, with a 80-8,000 Hz range was used f o r spectrographic a n a l y s i s . 2 . 3 2 2 . Selection and c l a s s i f i c a t i o n of utterances A l l audible and harmonic portions of non-crying utter-ances were sleeted for analysis except those i n which there was overlap of a d u l t - c h i l d voices or other interference. Each utterance was c l a s s i f i e d according to the context i n which i t occurred. The contexts were determined from d i r e c t i v e comments 76 TABLE 2.7 TAPING SESSIONS: CAB Age Adults present Location of child Other (wks) 5 Mother, two Es Bedroom; crib Awakening; pre-feed 7 Parents , two Es Living room: sofa With mother but watching pattern of sofa 8 Mother, E female Living room: sofa Mother talking to child 10 Mother, E female Living room: sofa Mother talking to child 12 Parents , two Es Living room: on father's lap, on floor Father talking to child, child playing alone 14 Mother, female Living room: sofa Mother playing with child E in cuddle-seat silently. Doll and rat-tle present 16 Parents E , female Living room: on fath-er's lap, with mother, with do 1 Laughter and squeals 18 Mother, female Living room: on blan- Appeared intriqued with E ket on floor blanket (Oj), squeals 20 Parents , two Living room: in a Vaccination that day, hic-Es "jolly-jumper", on blanket cups 22 Mother, E female Living room Feeding. Intriqued with bib (Oi) 77 TABLE 2.8 TAPING SESSIONS: AMG Age (wks) Adults Dresent Location of child Other Mother, female E None Mother, female E Mother, female E, psychologist Father, male E Living room: crib, mother's lap, crib Living room: crib Kitchen: tub Bedroom: crib Living room: on mother's lap Kitchen Mother, female E Kitchen: crib Rattle mobile in crib. Mother whis-pering. Concentration on mobile Mother whispering After Bayley test Watching Christmas tree and gifts Responded vocally to smile, silently to sight of microphone Watching rattle and squeaker toy 78 TABLE 2.9 TAPING SESSIONS: AMR Adults present Location of child Other* Mother, female E Mother, female E Mother, female E Mother, female E Mother, female E Living room: sofa Living room Mother hoding him, then by himself Responded to backrub vocally Living room: sofa Frequent whines Living room: on floor Child's room: crib Grunting and crying as well as cooing Very vocal when alone and watching mobile of butterflies (0}) . Silent when new toy introduced On early tapes, Mother was very talkative. In many cases, her utterances overlapped with the child's utterances. 79 TABLE 2.10 TAPING SESSIONS: JLR Age (wks) Adults present Location of child Other 14 16 Parents, female E Father, male E Mother, female E Mother, female E Mother, female E Living room: sofa, with mother Living room: on father's lap, then on floor Living room, then quiet room on bed Child's room: in crib Child's room: in crib, then on table Watching colorful block Watching pink mus- . ical toy (0X) Rattle (0i). All utterances sounded similar (monotone) Watching clown (Oj) mobile and stuffed dog (0 :). Seemed to respond differently to each toy (monotone) At first responding to mobile (0i) in crib. Diaper changed and vocalizations seemed to change also. At sight of microphone (02) child vocalized more. 80 TABLE 2.11 TAPING SESSIONS: DAE Age (wks) Adults present Location of child Other 5 Parents, female E Living room: in cuddle-seat Child has rash. Squeals 7 Parents, female E Living room Shots that day. Made acoustically interesting sounds when feeding 10 Parents, female E Living room Hiccups, squeals 13 Mother, female E Living room: in cuddle-seat Tried to 'stand on head* 16 Mother, female E Living room Sounds of wind and saw in background 81 TABLE 2.12 TAPING SESSIONS: MJK Age (wks) Adults present Location of child Other 5 Parents , female E Living room Child crying. Parents talking to him. 8 Mother, female E Living room: sofa Watching mobile, using smiles as response. 10 Mother, female E Living room Active but not very vocal. Responds to tickling at end. 13 Mother, female E Living room Mother very active 16 Mother, female E Living room Teething. Dog enters room. Many aperiodic sounds. 82 on the tape and from the w r i t t e n r e c o r d of each t a p i n g s i t u a t i o n . They were d e f i n e d as f o l l o w s . ( 1 ) C h i l d alone - Si C h i l d v o c a l i z i n g w i t h no apparent r e f e r e n t ; ( 2 ) C h i l d w i t h o b j e c t = S+0; C h i l d v o c a l i z i n g w h i l e f i x a t e d , v i s u a l l y or t a c t f u l l y on an o b j e c t ; and ( 3 ) C h i l d w i t h a d u l t = S+A ( f u r t h e r s u b c a t e g o r i z e d i n t o C h i l d w i t h mother = S+M, C h i l d w i t h f a t h e r = S+F, C h i l d w i t h E = S+E) i C h i l d v o c a l i z i n g w i t h i n f i v e seconds a f t e r a d u l t ' s v o c a l i z a t i o n . A lthough t h i s i s a l i m i t e d d e f i n i t i o n of c h i l d i n c o n t e x t w i t h a d u l t , i t was f e l t t h a t a broader d e f i n i t i o n ( i . e . , c h i l d i n the presence of an a d u l t ) would be too ambiguous f o r a n a l -y s i s , s i n c e the c h i l d was u s u a l l y i n the presence of at l e a s t one a d u l t . 2 . 3 2 3 . P r o d u c t i o n of spectrograms Narrow-band spectrograms (4-5-Hz f i l t e r bandwidth) and a s s o c i a t e d amplitude s e c t i o n s were made f o r each u t t e r a n c e . The r e c o r d i n g , reproduce and marking gains were o p t i m a l l y a d j u s t e d f o r each spectrogram to e l i m i n a t e extraneous tape n o i s e and minimize s i g n a l d i s t o r t i o n . S ince i n t e n s i t y was not measured (due to non-standardized r e c o r d i n g c o n d i t i o n s i n the d i f f e r e n t homes w i t h t h e i r d i f f e r e n t n o i s e l e v e l s ) , i t was not c o n s i d e r e d necessary to m a i n t a i n a c o n s t a n t g a i n l e v e l . However, 83 the gains were g e n e r a l l y a d j u s t e d to g i v e a VU meter r e a d i n g of between 0 and - 2 dB. Each spectrogram was a l s o c a l i b r a t e d w i t h a 500-Hz r e f e r e n c e tone. Reference tone spectrograms were a l s o made every s i x hours to check f o r machine v a r i a b i l i t y . 2 . 3 3 . Measurement of fundamental frequency (F c) and d u r a t i o n  f o r the f i r s t s u b j e c t (CAB) The u t t e r a n c e was c h a r a c t e r i z e d by three or f o u r p o i n t s : a b e g i n n i n g - p o i n t (B-P), one or two 'middle'-points (M-P) and an end-point (E-P). The b e g i n n i n g and end of the harmonic p o r t i o n of the u t t e r a n c e was d e f i n e d by the onset and disappearance of a t l e a s t the t h i r d harmonic. P r e l i m i n a r y wide-band spectrograms w i t h amplitude d i s p l a y s were compared w i t h narrow-band s p e c t r o -grams of the same u t t e r s a n c e s . In the m a j o r i t y of cas e s , the t h i r d harmonic became v i s i b l e on the narrow-band s p e c t r o -grams a t the p o i n t where i n t e n s i t y was r e g i s t e r e d on the amplitude d i s p l a y s . In amplitude s e c t i o n s made a t the approx-imate c e n t e r of each u t t e r a n c e , the f i r s t three harmonics appeared, i n most ca s e s , to more i n t e n s e than the oth e r har-monics. Thus, i t was f e l t t h a t the use of a t l e a s t the t h i r d harmonic was important f o r the c h a r a c t e r i z a t i o n of the p e r i o d -i c p o r t i o n of the u t t e r a n c e , a l t h o u g h t h i s c r i t e r i o n may have produced a con s t a n t underestimate of the ' a c t u a l ' d u r a t i o n of the u t t e r a n c e as w e l l as somewhat d i f f e r e n t b e g i n n i n g and 84 end fundamental frequencies than may otherwise have been obtained. A'middle'-point was defined as a marked change of FQ occurring anywhere between B-P and E-P. It could be either a peak or a dip i n the Fo-contours. If there was. more than one marked change of frequency, the two most c h a r a c t e r i s t i c changes were chosen. It was f e l t that the method of c h a r a c t e r i z a t i o n gave general information as to the shape of the contour; fewer points would have f a i l e d to characterize the utterance r e a l -i s t i c a l l y . Since the time required to process one spectro-gram completely was about ten minutes, the measurement of more points was not f e a s i b l e . The duration of each utterance was calculated as the i n t e r v a l between B-P and E-P on the spectrogram. Accuracy was within 50 msec. Since i t was known that one spectrogram of 3 1 . 8 cm i n length represents 2 . 5 7 seconds, a transparent p l a s t i c template could be used f o r measurement where 1.23 cm = 100 msec. In preliminary analysis, i t was generally found that harmonics above the f i f t h were not c l e a r l y v i s i b l e . It was decided therefore to cal c u l a t e F Q by determining the frequency of the f i f t h harmonic and d i v i d i n g by f i v e . In a small per-centage of cases, even the f i f t h harmonic was not v i s i b l e . 85 In t h i s event, i t was necessary to e x t r a p o l a t e , by measuring the d i s t a n c e between the c e n t e r frequency of the f i r s t and t h i r d harmonics w i t h c a l i p e r s and then p l o t t i n g a f i f t h p o i n t at the same d i s t a n c e from the t h i r d . T h i s d i s t a n c e was then checked a g a i n s t that between the b a s e l i n e and the second har-monic or between the second and f o u r t h harmonic. On each c a l i b r a t i o n spectrogram, a m i l l i m e n t e r - t o - H z c o n v e r s i o n template was c o n s t r u c t e d i n the f o l l o w i n g manner: Two l i n e s p e r p e n d i c u l a r to the base l i n e were drawn on the spectrogram. A l i n e was then drawn from the i n t e r s e c t i o n p o i n t of the l e f t v e r t i c a l l i n e w i t h the b a s e l i n e to the i n t e r s e c t i o n p o i n t of the 500-Hz harmonic and the r i g h t v e r t i c a l l i n e . A second l i n e was drawn from the i n t e r s e c t i o n p o i n t of the l e f t v e r t i c a l l i n e w i t h the 500-Hz harmonic to the i n t e r s e c t i o n p o i n t of the r i g h t v e r t i c a l l i n e w i t h the 1000-Hz harmonic, and so on, to 6000 Hz. To t h i s r e s u l t i n g f i g u r e , a t r a n s p a r e n t m i l l i m e t e r graph sheet was f a s t e n e d , forming a completed template w i t h 10-Hz i n t e r v a l s . The d i s t a n c e from the b a s e l i n e to the f i f t h harmonic f o r each B-P, M-P and E-P was determined w i t h c a l i p e r s and then compared to the e q u i v a l e n t d i s t a n c e on the template to c o n v e r t i t to F . o In the c a l c u l a t i o n of the f i f t h harmonic, t o t a l estimated e r r o r was +k0 Hz ( i . e . , + 20 Hz f o r the c o n s t r u c t i o n of the 86 template and +20 Hz f o r the measurement). Since F Q was determined by a d i v i s i o n by f i v e , estimated e r r o r f o r F Q was +8 Hz. In those cases where e x t r a p o l a t i o n was necessary the e r r o r may have i n c r e a s e d to c a . +10-12 Hz. T h i s was con-s i d e r e d a c c e p t a b l e , s i n c e p r e l i m i n a r y a n a l y s i s i n d i c a t e d t h a t the v a r i a b i l i t y of the c h i l d r e n ' s v o c a l i z a t i o n s was i n excess of t h i s v a l u e . 2 . 3 3 1 . I n t r a - o b s e r v e r and i n t e r - o b s e r v e r r e l i a b i l i t y I n t r a - and i n t e r - o b s e r v e r r e l i a b i l i t i e s were determined f o r the measurements o b t a i n e d . A 10% sample of spectrograms was chosen randomly f o r remeasurement. Remeasurement of d u r a t i o n by the same and a second reader y i e l d e d values i d e n t i c a l to the i n i t i a l measurement. Hence, no s t a t i s t i c a l a n a l y s i s was necessary f o r the d e t e r m i n a t i o n of r e l i a b i l i t y . Remeasurement of fundamental frequency d i d y i e l d s l i g h t l y d i f f e r e n t r e s u l t s . An a n a l y s i s of v a r i a n c e was done, s e p a r a t e l y f o r B-P, M-P and E-P. Variance between the i n d i v i d u a l p o i n t s was compared w i t h the v a r i a n c e w i t h i n the f i r s t and second measurements, and an F - r a t i o determined. In a l l cases, the v a r i a n c e of the sample was much g r e a t e r than that w i t h i n measurements. (See Tables 2 . 1 3 and 2 . l 4 , a l s o Appendix A ) . I n t r a - and i n t e r - o b s e r v e r r e l i a b i l i t y was t h e r e f o r e c o n s i d e r e d to be a c c e p t a b l e . 87 i I n s e r t T a b l e s 2.13 and 2.l4 about here 2o3^«> Measurement of fundamental frequency ( F 0 ) and d u r a t i o n  f o r o t h e r s u b j e c t s . The methodology f o r the c h a r a c t e r i z a t i o n of the u t t e r a n c e and the measurement of d u r a t i o n remained unchanged f o r the o t h e r s u b j e c t s . Fundamental frequency was a l s o determined i n e s s e n t i a l l y the same manner. However, measurement of the d i s t a n c e between harmonics on a l l of the c a l i b r a t i o n spectrograms f o r the p i l o t s u b j e c t i n d i c a t e d t h a t the frequency c a l i b r a t i o n of the spec-t r o g r a p h was v i r t u a l l y c o n s t a n t . I t was c o n s i d e r e d uneconom-i c a l to continue to c o n s t r u c t new templates. A standard, t r a n s -parent p l a s t i c template was designed from the templates f o r the f i r s t s u b j e c t . In order to check the v a l i d i t y of the template, r e f e r e n c e tone c a l i b r a t i o n spectrograms c o n t i n u e d to be made and measured throughout the study. I n s i g n i f i c a n t v a r i a t i o n was noted, and hence the template was c o n s i d e r e d v a l i d . 88 TABLE 2.13 INTRA-OBSERVER RELIABILITY: ANALYSIS OF VARIANCE FOR FUNDAMENTAL FREQUENCY (CAB) Source SS d f MS F Between utterances (B-P) Within utterances (B-P) 121.68 . 3.6895xl05 1 36 121.68 10,249.0 0.01 Between utterances (M-P) Within utterances (M-P) 44.237 3.1662xl05 1 36 44.237 8,795.0 0.01 Between utterances (E-P) Within utterances (E-P) 136.42 2.6117x105 1 36 136.42 7,254.6 0.02 TABLE 2.14 INTER-OBSERVER RELIABILITY: ANALYSIS OF VARIANCE FOR FUNDAMENTAL FREQUENCY (CAB) Source SS d f MS F Between utterances (B-P) Within utterances (B-P) 107.79 3.6929x10s 1 36 107.79 10,258.0 0.01 Between utterances (M-P) Within utterances (M-P) 437.92 3.0953x105 1 36 437.92 8,597.9 0.05 Between utterances (E-P) Within utterances (E-P) 50.947 2.6283xl05 1 36 50.947 7,300.9 0.01 CHAPTER 3 Results 3 . 0 . D e f i n i t i o n of age l e v e l and i n t e r p r e t a t i o n of results A l l chronological ages are expressed i n terms of weeks between b i r t h and recording or test data, a l l values being rounded to the nearest week (e.g., 3 weeks, 4 days = 4 weeks). Since a l l Ss were not recorded at the same age i n t e r v a l s , there are instances where no values appear i n the tables. 3.1. Duration Means and standard deviations of duration were calculated f o r every c h i l d at each age l e v e l , as i n Table 3»1» Insert Table 3 . 1 about here For a l l subjects but MJK, the mean duration tended to increase with age, from ca. 200 msec at 5 weeks to 400-700 msec at 14 weeks and beyond. Observation and hand-plotting showed that the variance was not constant but increased exponentially with age. For this reason, the l i n e a r regression of l o g g of duration on age was calculated to produce a better f i t (where y = e a + b x r e f e r to Appendix B f o r d e t a i l s ) . As indicated i n Figure 3.1, 89 TABLE 3.1 DURATION: MEANS AND STANDARD DEVIATIONS (All values to nearest msec) Age (in weeks) Subject Item 5 7 8 9 10 11 12 13 14 15 16 18 20 22 CAB Mean 250 220 226 - 322 - 291 475 - 732 300 560 535 SD 0 45 114 - 251 - 167 267 - 663 195 416 412 N 1 5 21 - • 41 - 11 14 - 46 15 5 37 AMG Mean 213 290 - 258 - - 358 - 635 426 - - -SD 159 200 - 143 - - 348 - 304 263 - - -N 16 77 - 13 - - 24 - 41 46 - - -AMR Mean . a a 180 375 - 177 186 - 584 - - - -SD - - 71 290 - 69 88 - 396 - - - -N - - 10 56 - 22 21 242 - - - -JLR Mean 239 440 - 357 - - - 326 - 541 - - -SD 127 375 - 222 - - - 193 - 418 - - -N 33 99 - 179 - - - 137 - 94 - - -DAE Mean 217 364 - - 443 - - 385 - 680 - - -SD 76 166 - - 336 - - 288 - 431 - - -N 3 33 - - 46 - - 33 - 76 - - -MJK Mean 390 - 354 - 244 - 534 365 - 430 - - - ' SD 304 - 199 - 134 - 431 249 - 307 - - -N 35 - 14 - 26 16 50 - 105 - - -Note. — Except as noted, missing values indicated no recording session at age designated. Recording made, but no viable utterances•produced. 91 the regression lines were s i g n i f i c a n t (p_ < . 0 1 ) f o r the same Insert Figure 3 « 1 about here f i v e Ss (for MJK, p_ > . 0 5 ) . B a r t l e t t s ' test indicated that the f i v e s i g n i f i c a n t regressions were homogeneous f o r variance ( x 2 - 1 * 5 3 5 0 6 , p_ > . 0 5 ; c f . Appendix C f o r d e t a i l s ) . Consequently, the slopes of the f i v e regression equations could be compared. A s i g n i f i c a n t difference i n ages of the c h i l d r e n at which recordings were made necessitated an adjust-ment of the means for age. It was noted that the adjusted means differed, s i g n i f i c a n t l y = 4 . 8 5 ^ 8 , £ < . 0 0 1 ) , and that the slopes also yielded a s i g n i f i c a n t F-ration ( F ^ i ^ g ^ = 1 1 2 . 5 8 0 9 , p_ < . 0 0 1 ) . This would indicate that the duration of the harmonic portion of utterance increases exponentially with age f o r the f i v e children, but at a d i f f e r e n t rate f o r each c h i l d . 3 . 1 1 . Comparison of utterances with one and two middle-points To compare the duration of those utterances with one middle-point (M-P) and those with two, Student's t-tests were performed. One of two computer test routines was u t i l i z e d , as outlined i n B j e e r l i n g and Seagreaves ( 1 9 7 1 , pp. 8 0 - 8 3 ) : Formula ( 1 ) which assumes only that the populations are normal; Figure 3.1. Regression of Log of Duration on Age. 4.0 x n AGE Cwks) *p_ < ,01 **£ < .001 93 or Formula ( 3 ) , used when population variances are equal. For a l l S_s but DAE, population variances were not equal; hence, Formula (1 ) was used i n f i v e of the six te s t s . Since with Formula (1 ) a t'-value i s calculated rather than a t-value, determination of sig n i f i c a n c e necessitates the cal c u -l a t i o n of the c r i t i c a l value of t*, a more accurate estimate of p r o b a b i l i t y (Snedecor and Cochrane, 19^7» pp. I l 4 - l l 6 ; c f . Appendix D f o r d e t a i l s of c a l c u l a t i o n ) . For a l l S_s but CAB, the duration of utterances with one M-P was s i g n i f i c a n t l y shorter than those with two; across S_s duration of utterances with one M-P ranged from ca. 320-450 msec, whereas f o r those with two, i t ranged from ca. 650-1000 msec, as shown i n Table 3 * 2 . Insert Table 3 » 2 . about here 3 . 2 . Fundamental frequency (FQ ) For each utterance, "derived means'1 f o r beginning-point (B-P), middle-point (M-P), and end-point (E-P) were determined. In the analysisof utterances with one M-P, i t appeared that there were four major F^-contours to be considered: r i s i n g , f a l l i n g , r i s i n g - f a l l i n g , and f a l l i n g - r i s i n g . In the f i r s t tv/o cases, the arithmetic mean was calculated. In the l a t t e r two, i t was TABLE 3.2 STUDENT'S t-TESTS OF DURATION OF UTTERANCES WITH ONE MIDDLE-POINT VS THOSE WITH TWO MIDDLE-POINTS (All values for means and SD's to nearest msec) Subject One middle-point Mean SD df Two middle-points Mean SD df t' t' .001 CAB 432 397 186 1011 834 8 2.073 2.302a AMG 349 252 196 730 340 19 4.885* 3.852 AMR 367 293 260 847 381 89 10.881* 3.431 JLR 328 231 468 779 384 72 9.764* 3.448 MJK 328 229 196 658 361 48 6.099* 3.527 DAE 455 334 166 896 408 23 5.871*b -Note. — t'-value calculated by Formula (1); cf. Appendix D. a t'-probability = t' k t-value calculated by Formula (3), p_ < .001; cf. Appendix D for details. 95 f e l t t h a t the a r i t h m e t i c mean would unduly weight B-P and E-P , which were approximately symmetrical w i t h r e s p e c t to frequency, w h i l e f a l l i n g to account f o r the d i v e r g e n t M-P. T h e r e f o r e , the d e c i s i o n was made to weight M-P by a f a c t o r or two, the mean then b e i n g c a l c u l a t e d by the f o r m u l a : (B + 2M + E)/4. The a n a l y s i s of u t t e r a n c e s w i t h two M-P showed that there were two b a s i c c o n t o u r s : r i s i n g - f a l l i n g -r i s i n g and f a l l i n g - r i s i n g - f a l l i n g . S ince i t c o u l d not be o b s e r v a t i o n a l l y d i s c e r n e d whether any p a r t i c u l a r p o i n t was weighted w i t h r e s p e c t to the o t h e r s , the a r i t h m e t i c mean was c a l c u l a t e d f o r both c u r v e s . At each age l e v e l f o r every c h i l d , means and standard d e v i a t i o n s were c a l c u l a t e d s e p a r a t e l y f o r B-P , M-P, and E-P , as w e l l as f o r the d e r i v e d means. Due to l i m i t a t i o n s i n the computer program, i t was only p o s s i b l e to use one M-P from each u t t e r a n c e . Given an u t t e r a n c e w i t h two M-P, t h a t one was chosen f o r a n a l y s i s which d e v i a t e d most from B-P and E-P s i n c e i t b e s t f u l f i l l e d the c r i t e r i a l d e f i n i t i o n of M-P as a marked change i n F q ( c f . S e c t i o n 2.33). No trends were apparent between c h i l d r e n f o r FQ a c c o r d i n g to the summary of means and standard d e v i a t i o n s a t each age. An examination of the F Q - c o n t o u r s as i n d i c a t e d i n F i g u r e s 3.2 - 3.7 — t a b l e s of values f o r which may be found i n Appendix E — p r o v i d e s the f o l l o w i n g d e s c r i p t i o n : 96 I n s e r t F i g u r e s 3.2 - 3*7 about h e r e . CAB ( F i g u r e 3.2); From the s i n g l e u t t e r a n c e recorded a t 5 weeks, which had a f a l l i n g contour, there was a t r e n d toward a r i s i n g - f a l l i n g contour i n which B-P was h i g h e r than E-P. AMG (F i g u r e 3»3)» A r i s i n g - f a l l i n g contour was noted a c r o s s s e s s i o n s , B-P b e i n g h i g h e r than E-P on most o c c a s i o n s * AMR(Figure 3*4)t From 8-15 weeks, both f a l l i n g and r i s i n g -f a l l i n g contours were e v i d e n t . Note t h a t at 15 weeks, the r e c o r d i n g s e s s i o n f o r which y i e l d e d 60% of the t o t a l u t t e r -ances a n a l y z e d , a f a l l i n g contour was e v i d e n t . JLR ( F i g u r e 3.5) J Both a f a l l i n g and a r i s i n g - f a l l i n g contour i n which B-P was h i g h e r than E-P appeared. DAE ( F i g u r e 3*6) j A r i s i n g - f a l l i n g contour was noted a c r o s s s e s s i o n s ; B-P exceeded E-P on most o c c a s i o n s . MJK ( F i g u r e 3*7)J Over a l l , a r i s i n g - f a l l i n g contour was e v i d e n t , i n which B-P f r e q u e n t l y exceeded E-P. Across a l l c h i l d r e n there was a t r e n d towards a drop i n F Q a t the end of the u t t e r a n c e and towards a r i s i n g - f a l l i n g contour i n which B-P was h i g h e r than E-P. For B-P, M-P, E-P and the d e r i v e d means, a l i n e a r r e g r e s -s i o n of fundamental frequency on age was c a l c u l a t e d f o r each Figure 3.2. Means for Fundamental Frequency: CAB. Beginning-Point Middle-Point 7 8 10 12 x = AGE (wks) (continued on next page) 86 Figure 3,4. Means for Fundamental Frequency: AMR 450 O y 1 m 350 S I! 300 250 Beginning-Point .Middle-Point End-Point Derived Mean 9 11 x s AGE (wks) .12 1 v.SJ i i 450 .. N X & 400 1 e II > > 350 300 250 " Figure 3,5, Means for Fundamental,Frequency.: JLR. Beginning-Point Middle-Point ^sj End,- Point Derived Mean 9. 14 16 x = AGE Cwks). Figure 3.6. M^ ans for Fundamental Frequency; DAE. r.rrt x 55 AGE (wks) x s AGE (wks) 104 c h i l d ( c f . Appendix F ) . Although not a l l r e g r e s s i o n s were s i g n i f i c a n t , a t l e a s t one out of f o u r was s i g n i f i c a n t f o r each c h i l d (p_<.05-.001). Only f o r JLR were a l l f o u r r e g r e s s i o n s s i g n i f i c a n t . Except f o r CAB (where the three s i g n i f i c a n t r e g r e s s i o n s were p o s i t i v e ) , s i g n i f i c a n t r e g r e s s i o n s were n e g a t i v e i n s l o p e ; t h a t i s , the F Q at a p a r t i c u l a r measured p o i n t g e n e r a l l y decreased w i t h i n c r e a s i n g age. However, these n e g a t i v e r e g r e s s i o n s d i d not n e c e s s a r i l y r e p r e s e n t the the same measured p o i n t ( i . e . , B-P, M-P, E-P) a c r o s s c h i d r e n . Since there were many d i f f e r e n c e s among c h i l d r e n w i t h r e s p e c t to number of o b s e r v a t i o n s and s i g n i f i c a n c e and s l o p e of r e g r e s s i o n s , no s t a t i s t i c a l cross-comparisons c o u l d be per-formed. 3 . 2 1 . W i t h i n - u t t e r a n c e range The d i f f e r e n c e between the maximum and minimum p o i n t s f o r each u t t e r a n c e was c a l c u l a t e d as a measurement of w i t h i n -u t t e r a n c e v a r i a t i o n ( i . e . r a n g e ) . Based on means and standard d e v i a t i o n , a l i n e a r r e g r e s s i o n of range on age was c a l c u l a t e d f o r every c h i l d , as i n F i g u r e 3.8 ( c f . a l s o Appendix G). I n s e r t F i g u r e 3.8 about here Figure 3.8. Regression of Within-Utterance Range on Age. 175" 106 With one exception (JLR), these regressions were s i g n i f i c a n t for a l l jSs. DAE had, ear ly on, a notably higher w i t h i n -utterance range than the others , but by l 6 weeks, was wi th in the 72-96 Hz range common to a l l . But for the four s i g n i f i c a n t regress ions , which had a p o s i t i v e s lope, B a r t l e t t ' s test for homogeneity of variance was performed, and the variances were found to d i f f e r s i g n i f i c a n t l y ( x 2 = 8 3 . 0 8 3 1 5 , p_ < .QOOl, c f Appendix C for d e t a i l s ) . The four regressions could not, therefore , be compared. As f or d u r a t i o n , the wi th in-ut terance range of those utterances with one M-P contrasted with those with two were examined by means of Student's t - t e s t s . Again, one of the two formulas (discussed i n Sect ion 3 * 1 and Appendix C) was employed. For a l l S_s but DAE, Formula ( 3 ) was used. The re su l t s ind ica te a s i g n i f i c a n t l y greater wi th in-ut terance range for utterances with two M-P (at l east p_ . 0 5 ) . As can be seen i n Table 3 * 3 , the means of wi th in-ut terance range general ly var ied between .70-90 Hz for utterances with one M-P compared with 115-155 Hz for utterances with two M -P. For DAE, both means were c a . 125 Hz, although the variance was greater for those utterances with one M -P. Insert Table 3 .3 about here 107 TABLE 3.3 SHJDENT'S t-TESTS OF VttTHIN-UTTERANCE RANGE LN UTTERANCES WITH ONE VS TWO MIDDLE-POINTS (All means and SD's to nearest Hz) Subject One middle-point Two middle-points t Mean SD df Mean SD df CAB 88 86 186 155 69 8 2.306* AMG 79 58 196 136 46 19 4.237** AMR 71 52 260 116 55 89 6.947** JLR 77 103 468 139 100 72 4.735** MJK 89 83 196 151 96 48 4.544** DAE 122 140 166 125 75 23 0.165a Note: t-value calculated by Formula (3); cf. Appendix D. a t'-value calculated by Formula (1); t'.05 = 2.454; cf. Appendix D for details *p_<.021 **p_<.001 109 3 . 3 . Regression of within-utterance range on duration A l i n e a r regression analysis of within-utterance range on duration was performed. Since previous analyses (cf. Tables 3 .2 and 3 * 3 ) indicated that utterances with one and two M-P generally d i f f e r e d s i g n i f i c a n t l y f o r range and duration, the regressions were calculated separately f o r each group. Sign-i f i c a n t regressions were noted f o r a l l but MJK i n the group with one M-P and f o r a l l but AMG and DAE i n the group with two M-P (cf. Figures 3*9 - 3 . 1 0 ; i n d i v i d u a l data points and regressions may be found i n Appendix H). Thus, f o r most Ss, an increase i n utterance length evinces a concomitant increase i n within-utterance range. Insert Figures 3«9 - 3*10 about here 3 . 4 . Utterances according to context A frequency count was made of the t o t a l number of utter-ances measured fo r each infant and of the number of u t t e r -ances within the following contexts at each age l e v e l for every S: ( 1 ) Child alone (S); ( 2 ) Child with Adult (S+A); (3 ) Child with Object (5+0). The percentage of utterances in each of these categories was then calculated over the Regression of Within-Utterance Range on Duration: Utterances with one Middle-Point. -4-CAB O <9 -* y JLR 0 " 0 y AMG A — * ** y MJK y AMR « ** y DAE •« y 1 60.00 + 0.6408x 43.17 + 1.036x 43.97 + 1.007x 78.87 + 0.3197X 47.17 + 0.6426X 75.45 + 1.030x 1000 1500 2000 x = DURATION (msec) 2500 3000 aft p_ < .002 D < .001 Figure 3.10. Regression of Within-Utterance Range on Duration: Utterances with two Middle-Points ; 275 •• 225 •• % R" 175 i 125 II 75 •• 25 — I — 500 1Q00 1 1 — 1500 2000 x = DURATION (msec) CAB © <3> * y = 97.90 + 0.5636x JLR O—O ** y = 59,77 + l.Ollx AMG ± — * y = H5.5 + 0.2746X MJK A—A * y = 100.5 + 0.7730X AMR • — * * y = 55.57 + 0,7111x DAE Q " , , a y = 126.9 - O.OLSlx 1 1 2500 3000 * p_ < .05 ** p_ < .001 i — 1 i— 1 o I l l t o t a l number of utterances f o r each S. The use of the t o t a l number of utterances as a basis f o r c a l c u l a t i o n affords a more perspicuous analysis of utterances i n context longitud-i n a l l y and f o r each session, as can be seen i n Figures 3 * 1 1 -3 .16 (in which the value above the bar denotes the number of tokens comprising the given type). Insert Figures 3 . 1 1 - 3 » l 6 about here Across Ss, a general increase i n amount of v o c a l i z a t i o n over age i s noted. However, Ss d i f f e r e d i n t o t a l number of utt e r -ances produced: for JLR, twice as many utterances were recorded as f o r the others; CAB, although producing approximately the same number of utterances as a l l but JLR, was recorded over ten sessions rather than f i v e or s i x . In d i v i d u a l l y , results were as follows: CAB (Figure 3 . 1 1 ) : Over age, there was v a r i a b i l i t y i n t o t a l amount of v o c a l i z a t i o n and amount per context. There were more tokens of the type S+0 during the l a t e r recording sessions. AMG (Figure 3 * 1 2 ) : Generally, there were more tokens of the type S than S+A. The recording f o r 7 weeks i s notable, since a l l utterances were i n the context S+0. AMR (Figure 3 . 1 3 ) : From 8-12 weeks, there were more tokens of the type S+A than S or S+0. During the f i n a l recording 50 46 42 34 g 30 P & 26 w u 22 18 Figure 3 .11. Utterances according to Context for CAB: Percentage/total number i Total Utterances: 196 Values over bars = number of observations S S+A S+0 14 4 10 6 22 1 3 .19 2'4 10 . 3 2 10 12 14 16 x = AGE (wks) 18 20 22 Figure 3.12. Utterances according to Context for AMG: Percentage/total number Figure 3.13. Utterances according to Context for AMR: Percentage/total number. x = AGE (wks) Figure 3.14. Utterances according to Context for JLR: Percentage/ total number Total Utterances: 542 Values over bars = number of observations S+A S+0 137 x = AGE (wks) w <; P M O, 50 46 42 -38 •• 34 30 26 f 22 18 14 10 6 2 Figure 3.15. Utterances according to Context for DAE: Percentage/total number . Total Utterances: 191 Values over bars = number of observations 2 1 S^+A S+0 29 .17 23 10 10 . 13 x = AGE(wks) 17 16 CD 50 46 42 38 + 34' g 30 ft % 26' w p.* " 22' >> 18-14-10 r 6-2 + Figure 3.16. Utterances according to Context for MJK: Percentage/total number. Total Utterances: 246 Values over bars = number of observations 2 9 s S+A S+0 12 em 1 2 1 5 1 2 6 2 1 ML 7 Lf 31 10 12 x = AGE (wks) 13 16 118 s e s s i o n , 60% of the t o t a l u t t e r a n c e s were produced, most of which were i n the context S+0. JLR ( F i g u r e 3.l4): Amount of v o c a l i z a t i o n was f a i r l y c o n s t a n t over age. For her, there were more tokens of the type S+0 than f o r the other S_s. R e l a t i v e l y few of the u t t e r a n c e s were of the type S+A. DAE(Figure 3.15): No d e f i n i t e trends appeared f o r DAE. R e l a t -i v e l y few u t t e r a n c e s of the type S+0 were r e c o r d e d . MJK ( F i g u r e 3.l6): On the e a r l y r e c o r d i n g s , there were more tokens of S than S+A. From 12 weeks on, t h i s t r e n d r e v e r s e d . 3.4l. H o t e l l i n g ' s T t e s t s of context c o n t r a s t s f o r funda-mental frequency For the purpose of c o n t r a s t i n g the c h i l d ' s F q i n d i f f e r e n t s i t u a t i o n s , u t t e r a n c e s were c a t e g o r i z e d a c c o r d i n g to the f o l l o w i n g c o n t e x t s : (1) C h i l d alone (S); (2) C h i l d w i t h Mother (S+M); (3) C h i l d w i t h Father (S+F); (k) C h i l d w i t h Experimenter (S+E); (5) C h i l d w i t h one Object (S+OjJ> (6) C h i l d w i t h second Object (S+0 2); (7) C h i l d w i t h t h i r d Object (S+0^). Two s e t s of v a r i a b l e s were analyzed f o r each c o n t r a s t : (1) B-P, M-P and E-P, and (2) B-P, M-P, E-P, and w i t h i n - u t t e r -ance range. Since i t p r o v i d e s a m u l t i v a r i a t e a n a l y s i s of means ( i . e . , s i m u l t a n e o u s l y examines more than one v a r i a b l e on two s i m i l a r p o p u l a t i o n s ) , the H o t e l l i n g ' s T 2 t e s t was used tc c o n t r a s t the context groups. However, only those groups 119 c o u l d be analyzed i n which there were more than three u t t e r -ances; consequently, out of a p o s s i b l e 87 c o n t r a s t s f o r data set (1) and an e q u i v a l e n t number of c o n t r a s t s f o r set ( 2 ) , o n l y kO t e s t s c o u l d be performed f o r each set of v a r i a b l e s . R e s u l t s are summarized i n Tables 3 *4 - 3»9» I n s e r t Tables 3 *4 - 3 . 9 about here Of the 40 t e s t s of B-P, M-P, and E-P onl y , 30 showed n o n - s i g n i f i c a n t r e s u l t s , i m p l y i n g that i n the m a j o r i t y of case s , the c h i l d r e n d i d not v o c a l i z e d i f f e r e n t l y i n terms of F i n the con t e x t s d e f i n e d above. No s i g n i f i c a n t c o n t r a s t s o i n t o t o were noted f o r the f o l l o w i n g c a t e g o r i e s ! S+0 x S+M 2 2 ( s i x T t e s t s performed) and S+0 x S+E (two T t e s t s performed). The remaining 25$ of s i g n i f i c a n t T 2 t e s t s were d i s t r i b u t e d over Sjs as f o l l o w s ; (1) S x S+Ex 1 s i g n i f i c a n t c o n t r a s t / 1 T 2 t e s t performed ( i . e . , JLR: l / l ) (2 ) S x S+M: 2/lk ( AMR; l / 2 , JLR: l / l , CAB: 0 / 4 , AMG: 0 / 2 . DAE: 0 / 2 , MJK: 0 /3)5 (3 ) S x S+F: l/k ( DAE: l / l , CAB: O / l , AMG: O / l , MJK: o / D ; (4 ) S x S+0: 2 / 8 ( JLR: 2 / 4 , CAB: O / l , AMG: O / l , MJK: o / l ) ; TABLE 3.1+ HOTELLING'S T?" TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: CAB Age (wks) Context N Nature of measurement: Mean/SD (All values to nearest Hz) B-P M-P E-P Range Age (wks) Contrasts df 2 T Associated F-value 5 S 1 328/ 0 314/ 0 264/ 0 64/ 0 8 S X S+Ma 3 16 1.388 0.411 7 S 5 322/ 27 352/ 31 338/ 23 50/ 35 S X S+M^  4 , 15 6.693 1.394 8 S 13 315/ 45 326/ 42 317/ 51 30/ 31 10 S X S+Ma 3 37 1.254 0.397 S+M 7 333/ 31 339/ 39 320/ 64 53/ 34 S X S+Mb 4 36 1.810 0.418 10 S 22 365/128 393/118 365/118 52/ 37 16 S X S+Ma 3 , 31 1.461 0.458 S+M 19 352/ 72 372/ 55 343/ 65 60/ 51 S X S+M5 4 30 1.461 0.332 12 s c 3 286/ 30 364/ 38 361/ 43 101/ 32 S X S+Fa 3 15 9.642 2.836 S+MC 2 . 407/106 442/ 42 390/ 99 57/ 49 S X S+F5 4 14 11.61 2.391 c S+F 2 415/ 44 390/ 37 398/ 33 57/ 35 S X s+oa 3. 18 1.853 0.556 S+EC 4 373/ 26 356/ 12 340/ 6 33/ 29 S X s+ob 4 » 17 2.684 0.570 14 S+O 14 333/ 66 373/ 27 327/ 51 74/ 57 S+M X S+Fa 3. 20 11.09 3.360* • 16 S 15 374/ 51 441/ 75 388/ 78 101/ 79 S+M X S+F^  4. 19 13.16 2.841 S+M 20 395/ 79 436/ 45 374/ 68 99/ 59 S+M X s+oa 3 23 3.604 1.105 S+F 4 432/ 71 540/233 536/172 179/181 S+M X s+ob 4. 22 4.381 0.964 S+O 7 364/ 63 399/ 50 360/ 57 67/ 39 S+F X s+o° - - -(cont inued on next p age) TABLE 3.4 (continued) 2 HOTELLING'S T TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: CAB Nature of measurement: Mean/SD Age Context N (All values to nearest Hz) Age Contrasts df T2 Associated (wks) B-P M-P E-P Range (wks) F-value 18 S+M 5 649/201 575/247 532/219 129/140 18 S+M x S+0ja 3, 10 6.375 1.771 S+0! 9 724/309 830/227 644/134 254/202 S+M x S+0!b 4, 9 6.419 1.204. S+02° 1 544/ 0 400/ 0 468/ 0 144/ 0 22 S X S+Ma 3, 11 5.467 1.542 20 Sc 3 460/ 71 435/ 75 308/101 164/ 24 S X S+M5 4, 10 10.86 2.088 S+FC 2 447/ 4 453/ 10 431/ 24 25/ 30 S X c S+E - -22 S 4 352/115 440/ 58 339/ 76 132/ 27 s X s+oa 3, 19 1.258 0.380 S+M 11 371/ 69 404/ 49 306/ 34 113/49 s X s+ob 4, 18 1.542 0.330 S+E 3 375/ 34 513/ 86 315/ 70 206/112 S+M X s+oa 3, 26 2.162 0.669 S+0 19 353/ 91 396/ 97 325/ 67 105/ 65 S+M X s+ob 4, 25 2.793 0.623 S+M X S+Fa 3, 10 14.13 3.926 S+M X S+Eb 4, 9 16.26 3.048 S+0 X S+Ea 3, 18 7.369 2.211 S+0 X S+Eb 4, 17 8.392 1.783 Hotelling's T tests of beginning-, middle-, and end-points only. Hotelling's T tests of beginning- middle-., and end-points and within-utterance range. . Insufficient degrees of freedom for contrast. . •'• p_ < .05 TABLE 3.5 HOTELLING'S T2 TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: AMG Age (wks) Context N Nature of measurement: Mean/SD (All values to nearest Hz) B-P M-P E-P Range Age (wks) Contrasts df T2 Associated F-value 5 Sc 14 413/ 36 425/39 397/ 51 42/ 33 12 S x S+Ma 3, 20 2.138 0.648 S+M° 2 383/ 13 439/ 38 347/ 13 92/ 51 S x S+Mb 4, 19 4.633 1.000 7 S+O 77 357/ 62 407/ 64 365/ 69 82/ 59 9 Sc 12 399/ 66 397/ 48 382/ 37 36/ 31 15 S x S+Fa 3, 36 0.676 0.214 S+M 1 404/ 0 444/ 0 372/ 0 72/ 0 S x S+F5 4, 35 0.825 0.190 12 S 16 393/ 68 403/ 58 359/ 61 86/ 44 S+M 8 364/ 55 373/ 60 328/ 39 61/ 49 16 S x S+M61 3, 41 0.085 0.027 15 S 30 368/ 75 405/ 67 309/ 65 114/ 62 S x S+Mb 4, 40 0.931 0.217 S+F 10 368/ 45 395/ 44 320/ 51 96/ 29 S+Ec 1 354/ 0 400/ 0 260/ 0 140/ 0 16 S 28 378/ 92 419/105 368/101 102/ 71 S+M 17 385/ 76 423/ 52 374/ 75 88/ 59 S+Oc 1 442/ 0 437/ 0 442/ 0 5/ 0 a Hotelling's T tests of beginning-, middle-, and end-points only. b Hotelling's T tests of beginning-, middle-, and end-points and within-utterance range. c Insufficient degrees of freedom for contrast. TABLE 3.6 HOTELLING'S T2 TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: AMR Nature of measurement: Mean/SD Age Context N (All values to nearest Hz) Age Contrasts df T2 Associated (wks) B-P M-P E-P Range (wks) F-value 8 Sc 2 293/ 30 308/ 4 293/ 4 28/ 14 9 S x S+M3 3, 51 2.307 0.740 S+M° 8 361/ 66 368/ 75 342/100 87/ 61 S x S+Mb 4, 50 2.522 0.595 9 S 18 330/ 61 355/ 52 307/ 78 66/ 46 12 S x S+Ma 3, 17 12.86 3.836-S+M 37 346/ 47 376/ 52 318/ 65 76/ 47 S x S+Mb 4, 16 12.87 2.709 S+Ec 1 360/ 0 386/ 0 276/ 0 110/ 0 11 S+M 22 382/ 55 372/ 47 347/ 49 44/40 15 S+M X S+Oa 3,237 1.212 0.401 12 S 5 427/ 84 455/ 21 431/ 31 63/ 61 S+M x S+0b 4,236 2.426 0.599 S+M 16 333/ 69 338/ 80 316/ 76 73/ 52 15 S+M 28 341/ 61 351/ 73 337/ 63 77/ 53 S+Ec 1 380/ 0 412/ 0 402/ 0 32/ 0 S+0 213 342/ 65 337/ 66 330/ 51 91/ 59 1 a Hotelling's T tests of beginning-, middle-, and end-points only. b Hotelling's T 2 tests of beginning-, middle-, and end-points and within-utterance range. c Insufficient degrees of freedom for comparison. * £ <.03 TABLE 3.7 HOTELLING'S T2 TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: JLR Nature of measurement: Mean/SD Age Context N (All values to nearest Hz) Age Contrasts df T 2 Associated (wks) B-P M-P E-P Range (wks) F-value 5 Sc 30 394/ 86 412/ 89 358/ 77 77/ 65 7 S x S+Ea 3, 63 10.17 3.286* S+M° 2 401/ 86 425/106 339/ 66 86/ 40 S x S+Eb 4, 62 10.24 2.441 S+Ec 1 332/ 0 335/ 0 338/ 0 6/ 0 S x S+0a 3, 73 8.545 2.772 7 S 48 414/126 421/131 414/107 135/139 S x S+0b 4, 72 8.563 2.055 S+FC 3 365/ 54 387/ 25 349/ 56 83/ 45 S+E x S+0a 3, 44 7.577 2.416 S+E 19 412/118 480/134 370/ 91 154/ 99 S+E x S+0b 4, 43 7.582 1.772 S+O 29 373/ 86 380/115 347/ 87 116/116 9 S x S M3 3,108 11.50 3.762** 9 S 97 352/ 63 346/ 50 336/ 56 56/ 51 S x S+Mb 4,107 12.79 3.110** S+M 15 372/120 319/ 54 310/ 36 77/ 94 S x S+0a 3,159 7.343 2.417 S+O 66 344/ 83 327/111 313/ 50 72/ 93 S x S+0b 4,158 19.06 4.657*** S+M x S+0a 3, 77 2.188 0.711 S+M x S+0b 4, 76 3.819 0.919 (continued on next page) TABLE 3.7 (continued) HOTELLING'S T2 TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: JLR Nature of measurement: Mean/SD Age Context N (All values to nearest Hz) Age Contrasts df T2 Associated (wks) B-P M-P E-P Range (wks) F-value 14 S+Oi 103 326/ 46 318/ 72 310/ 54 62/ 55 14 S+0 x S+02a 3,133 3.438 1.129 S+02 34 341/ 91 342/ 62 318/ 67 84/ 98 S+01 x S+02 4,132 4.532 1.108 16 S 24 314/ 53 347/ 53 327/ 49 81/ 42 16 S x s + 0 l a 3, 37 4.851 1.534 S+Oi 17 446/370 397/187 332/ 78 140/368 S x S+°ia 4, 36 13.53 3.121* S+02 50 331/ 49 340/ 72 297/ 51 107/ 56 a s+o 3c 3 337/ 35 346/ 93 279/ 7 117/ 11 S x S+02a 3, 70 8.559 2.774* S x S+0 2 4, 69 9.884 2.368 S+0 x S+02a 3, 63 8.989 2 904* S+0 x S+0 2 4, 62 28.07 6.695**** a Hotelling's T tests for beginning-, middle-, and end-points only. D Hotelling's T tests for beginning-, middle-, and end-points and within-utterance range. ° Insufficient degrees of freedom for contrast. *p_<.05 **2<.02 ***£<.01 TABLE 3.8 HOTELLING'S T2 TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: DAE Nature of measurement: Mean/SD Age Context N (All values to nearest Hz) Age Contrasts df T2 Associated (wks) . B-P M-P E-P Range (wks) F-value 5 Sc 2 334/ 88 360/ 88 310/ 48 52/ 37 7 S x S+Oa 3, 27 2.280 0.708 S+Fc 1 290/ 0 302/ 0 288/ 0 14/ 0 S x S+0b 4, 26 2.309 0.518 7 S+Ec 1 282/ 0 286/ 0 260/ 0 26/ 0 S+Fc 1 354/ 0 372/ 0 370/ 0 18/ 0 10 S x S+Fa 3, 37 10.42 3.294* S 5 369/ 64 424/134 345/75 108/110 S x S+F5 4, 36 10.50 2.422 S+O 26 328/ 84 372/171 336/107 81/123 13 S x S+Ma 3, 27 3.026 0.939 i o S 29 490/112 649/227 549/174 243/199 S x S+M5 4, 26 3.753 0.841 S+F 12 500/119 543/137 405/110 158/108 x S+M3, S+Ec 2 819/612 866/602 478/161 388/441 16 S 3, 69 6.301 2.041 S+Mc 3 497/142 569/224 432/ 58 242/151 S x S+Mb 68 8.725 2.089 13 S 10 363/107 400/ 88 400/ 89 125/ 86 S+M 21 428/182 486/265 411/200 132/111 S+EC 1 399/137 472/147 398/221 103/ 33 16 S 56 382/108 393/ 96. 369/ 85 83/ 66 S+M 17 348/ 72 352/ 46 315/ 64 70/ 69 S+Oc 3 330/ 12 347/ 27 313/ 46 41/ 58 a Hotelling's T 2 tests of beginning-, middle-, and end-points only. b Hotelling's T tests of beginning-, middle-, and end-points and within-utterance range. c Insufficient degrees of freedom for contrasts. * p<.05 TABLE 3.9 HOSTELLING'S T* TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: MJK Age (wks) Context N Nature of measurement: Mean/SD (All values to nearest Hz) B-P M-P E-P Range Age (wks) Contrasts df T2 Associated F-value 5 S 29 335/ 69 365/ 55 337/ 38 65/ 53 5 S x S+Fa 3, 30 4.196 1.311 S+F 5 298/ 26 320/ 35 308/ 28 33/ 23 S x S+Fb 4, 29 5.136 1.164 S+Mc 1 366/ 0 349/ 0 332/ 0 34/ 0 10 S x S+Ma 3, 17 4.594 1.370 8 Sc 12 442/264 463/236 352/102 174/223 S x S+M5 4, 16 5.470 1.152 S+Mc 2 345/ 86 322/ 67 337/ 7 71/ 4 S x S+0a 3, 13 1.519 0.439 10 S 12 372/158 390/130 342/ 92 91/131 S x S+0b 4, 12 6.433 1.287 S+M 9 320/ 56 334/ 42 297/ 47 68/ 32 S+M x S+0a 3, 10 3.035 0.843 S+0 5 319/ 91 365/109 359/160 81/54 S+M x S+0b 4, 9 3.368 0.632 (continued on next page) TABLE 3.9 (continued) HOTELLING'S T2 TESTS OF CONTEXT CONTRASTS FOR FUNDAMENTAL FREQUENCY: MJK Nature of measurement: Mean/SD Age Context N (All values to nearest Hz) Age Contrasts df T2 Associated (wks) B-P M-P E-P Range (wks) F-value 12 S+M 7 321/ 47 326/ 69 340/ 45 . 74/. 55 12 S+M x S+Fa 3, 11 14.38 4.055* S+F 8 328/ 44 378/ 71 281/ 69 130/ 52 S+M x S+Fb 4, 10 22.31 4.290** Sc 1 348/ 0 307/ 0 ' 266/ 0 82/ 0 13 . S x S+M3, 3, 43 7.531 2.399 13 S 26 367/139 445/241 391/216 123/128 S x S+M5 4, 42 9.230 2.154 S+M 21 286/ 32 353/ 57 296/ 43 82/ 38 S x S+M3 S+O 3 304/ 38 355/ 78 273/ 22 91/ 44 16 3,101 2.133 0.697 16 S 31 304/ 61 351/ 51 288/ 59 117/ 61 S x S+M5 4,100 2.486 0.604 S+M 74 331/100 366/ 82 305/ 77 110/ 65 a Hotelling's T tests of beginning-, middle-, and end-points only. D Hotelling's T tests of beginning-, middle-, and end-points and within-utterance range. c Insufficient degrees of freedom for contrast. *p_<.04 **p_<.03 129 ( 5 ) S+O^x S+Oj 1/2 ( JLR. 1 / 2 ) ; ( 6 ) S+M x. S+_E: 2/2 ( CAB: l / l , MJK: l / l ) ; and ( 7 ) S+M x S+E: l / l (CAB: l / l ) . An examination of B-P, M-P and E-P i n each s i g n i f i c a n t c o n t r a s t shows that B-P was o f t e n l e s s d i f f e r e n t i n the two groups ( 6 / 1 0 o c c a s i o n s ) than M-P or E-P (9/10 and 1 0 / 1 0 o c c a s i o n s , r e s p e c t i v e l y ) . Furthermore, these p o i n t s were not n e c e s s a r i l y symmetrical w i t h r e s p e c t to t h e i r F Q - c o n t o u r ; f o r example, i n c o n t r a s t S x S+E f o r JLR a t 7 weeks, M-P of type S_ i s lower than M-P of type S+E (421 Hz; 4 8 0 Hz) whereas E-P of type S i s h i g h e r than E-P of type S+E ( 4 l 4 Hz; 3 7 0 Hz). For F Q , however, the f o l l o w i n g c o n s i s t e n c i e s are noted: (1) S x S+A: In a l l f o u r cases (S x S+F, S_ x S+M twice, and S_ x S+E), the only trend noted was' that E-P r e p r e s e n t e d the mean minimum F Q f o r S+A. ( 2 ) S+M x S+F, or S+M x S+E: In the three cases noted, M-P f o r S+E or S+F represented the mean maximum F . 2 Of the f o r t y T t e s t s which i n c l u d e d w i t h i n - u t t e r a n c e range, 3 4 y i e l d e d n o n - s i g n i f i c a n t r e s u l t s , whereby the f o l l o w i n g groups y i e l d e d no s i g n i f i c a n t r e s u l t s i n t o t o : ( 1 ) S x S+F (4 t e s t s performed), ( 2 ) S+M x S+E (1 t e s t ) , ( 3 ) S x S+E (1 t e s t ) , (4) S+O x S+E (2 t e s t s ) , ( 5 ) S+M x S+O (6 t e s t s ) . The f i v e s i g n i f i c a n t c o n t r a s t s were d i s t r i b u t e d over Ss as f o l l o w s : 130 (1) S x S+0: 2 s i g n i f i c a n t c o n t r a s t s / 8 T t e s t s performed ( i . e . , JLR: 2/4, DAE: O / l , MJK: O / l , CAB: 0 / 2 ) ; (2) S x S+M: l / l 4 (JLR: l / l , CAB: 0 / 4 , AMG: 0/2, AMR: 0 / 2 , DAE: 0/2," MJK: 0 / 3 ) ; (3) S+Oj^ x S+_02: 1/2 (JLR: l / 2 ) ; and (k) S+M x S+F: 1/2 (CAB: O / l , MJK: l / l ) . In the c o n t r a s t s S x S+0, S x S+M, and S+M x S+F, the range was c o n s i s t e n t l y g r e a t e r f o r the second context group i n each case. 2 In sum, an aggregate of e i g h t T t e s t s were performed, i n which 15 t e s t s were s i g n i f i c a n t at the 5$ l e v e l of c o n f i -dence or b e t t e r . Some of these, however, are pro b a b l y s i g -n i f i c a n t by chance. D i s t r i b u t i o n of s i g n i f i c a n c e across c h i l d r e n d i d not appear to be random: JLR a p p a r e n t l y v o c a l -i z e d d i f f e r e n t l y f o r F Q i n d i f f e r e n t s i t u a t i o n s more o f t e n than the other c h i l d r e n ( 9 / 2 0 o c c a s i o n s ) and at an e a r l i e r age (7 weeks compared w i t h 10 weeks at the e a r l i e s t f o r the other Ss), whereas none of the s i x t e s t s performed f o r AMG reached s i g n i f i c a n c e . Comparing the r e s u l t s of the two d a t a s e t s , i t w i l l be noted t h a t f i v e of the s i g n i f i c a n t c o n t r a s t s f o r data set ( l ) f a i l e d to reach s i g n i f i c a n c e over a l l S_s. when range was i n c l u d e d (S x S+F, S x S+M, S x S+E. S x S+0, S+H x S+E), although one f u r t h e r c o n t r a s t (S x S+0) was s i g -n i f i c a n t . Again c o n s i d e r i n g the two sets of v a r i a b l e s , the f o l l o w i n g c o n s i s t e n c i e s c o u l d be noted: 131 (1) S x S+A: The only t r e n d appeared to be the occurrence of the mean minimum F i n the group S+A, i n which E-P was the o mean minimum F . o (2) S x S+0: The g r e a t e r range was found i n the S+0 group f o r those cases where s i g n i f i c a n c e was reached i n t e s t s f o r data s e t ( 2 ) . (3) S+M x S+F or S+M x S+E: In a l l cases, the mean maximum F Q (=M-P) and the g r e a t e r w i t h i n - u t t e r a n c e range were noted i n the c o n t e x t s S+F and S+E. 3.5* Summary of r e s u l t s Three major analyses were performed on the r e c o r d i n g s of i n f a n t v o c a l i z a t i o n s : (1) Regressions of a c o u s t i c f e a t u r e s on age, (2) R e l a t i o n s h i p s of F and d u r a t i o n , and (3) C o n t r a s t s of the c h i l d ' s v o c a l i z -o a t i o n s i n d i f f e r e n t c o n t e x t s . Of the r e g r e s s i o n s , not a l l were s i g n i f i c a n t . Two trends were, however, noted: (1) the e x p o n e n t i a l i n c r e a s e of the d u r a t i o n of the harmonic p o r t i o n of u t t e r a n c e s w i t h age, and (2) the l i n e a r i n c r e a s e of w i t h i n - u t t e r a n c e range on age. The r e l a t i o n of F to d u r a t i o n r e v e a l e d a g e n e r a l i n c r e a s e o i n w i t h i n - u t t e r a n c e range w i t h i n c r e a s i n g f l u c t u a t i o n and d u r a t i o n of u t t e r a n c e . The F -contour i t s e l f was noted to be 132 r i s i n g - f a l l i n g i n most c a s e s . A c c o r d i n g to c o n t e x t , i t appeared that c h i l d r e n of 5 - l 6 weeks v o c a l i z e d l e s s i n the presence of an a d u l t than alone or w i t h an o b j e c t . The great number of n o n - s i g n i f i c a n t c o n t r a s t s f o r H o t e l l i n g ' s T 2 t e s t s a l s o demonstrated that the c h i l d r e n g e n e r a l l y d i d not a l t e r t h e i r v o c a l i z a t i o n p a t t e r n g i v e n changes of s i t u a t i o n . However, the f a c t that 20% of the t e s t s were s i g n i f i c a n t demonstrates that the c h i l d r e n were at l e a s t capable of a l t e r i n g t h e i r F -contour as a change o i n s i t u a t i o n o c c u r r e d . CHAPTER 4 D i s c u s s i o n 4.1. L i m i t a t i o n s of experiment 4.11. Subject sample The sample s i z e l i m i t s the g e n e r a l i t y of a l l c o n c l u s -i o n s . Although chosen on the b a s i s of normal m e d i c a l and developmental h i s t o r i e s , the i n f a n t s demonstrated v a r i a b i l i t y i n development and a c o u s t i c f e a t u r e s a n a l y z e d . A l l trends w i l l have to be reviewed at a l a t e r date i n the co n t e x t of the l a r g e r study from which these Ss are drawn. 4.12. C l a s s i f i c a t i o n of data Data c o l l e c t i o n i n the home environment presupposes v a r i a b l e r e c o r d i n g s i t u a t i o n s w i t h i n and among Ss. Consequ-e n t l y , i n t r a - and i n t e r - s u b j e c t comparisons depend to a l a r g e extent on s u b j e c t i v e o b s e r v a t i o n s of the r e c o r d i n g s e s s i o n s . Lack of p r e c i s i o n i n these o b s e r v a t i o n s may have r e s u l t e d i n some erroneous comparisons; c f . , f o r example, F i g u r e s 3.11 - 3 . l 6 and the H o t e l l i n g ' s T 2 c o n t r a s t s , which were dependent on a c c u r a t e c l a s s i f i c a t i o n of u t t e r a n c e a c c o r d -i n g to c o n t e x t . C l a s s i f i c a t i o n was p a r t i c u l a r l y d i f f i c u l t f o r the r e c o r d i n g made of AMR at age 12 weeks. 133 134 4 . 1 3 » Measurement As mentioned i n S e c t i o n 2 . 3 3 » the number of measurements was l i m i t e d due to the l a b o r i o u s and time-consuming process i n v o l v e d i n producing and a n a l y z i n g spectrograms — approx-i m a t e l y 1500 spectrograms were pro c e s s e d . The somewhat a r b i t -r a r y c h o i c e of the onset and disappearance of the t h i r d har-monic as measurement c r i t e r i a f o r d u r a t i o n has p r o b a b l y y i e l d e d a c o n s t a n t underestimate of d u r a t i o n , as w e l l as a somewhat d i f f e r e n t F f o r B-P and E-P than might otherwise have been o o b t a i n e d . Although i t was attempted to measure only the har-monic p o r t i o n of an u t t e r a n c e at a l l times, some d i f f i c u l t y was encountered i n d i s t i n g u i s h i n g non-harmonic from harmonic p o r t i o n s i n the middle of c e r t a i n u t t e r a n c e s ; consequently the underestimate of d u r a t i o n may have been c o u n t e r b a l a n c e d i n some c a s e s . Although the measurement of B-P, M-P, and E-P gave an approximation of the F Q - c o n t o u r , a more i n v o l v e d a n a l y s i s which takes both F Q and d u r a t i o n i n t o account might prove more u s e f u l i n f u t u r e r e s e a r c h . k.lk. S t a t i s t i c a l a n a l y s i s For t h i s study, the major q u a n t i t a t i v e c r i t e r i o n f o r a n a l y s i s was c h r o n o l o g i c a l age. Developmental and s o c i a l data c o u l d o n l y be used d e s c r i p t i v e l y to suggest reasons f o r i n t r a - and i n t e r - s u b j e c t v a r i a b i l i t y , s i n c e there were seldom more than one or two s e t s of these d a t a . 135 Inter-subject v a r i a b i l i t y according to chronological age li m i t e d the number of possible cross-comparisons, p a r t i c -u l a r l y f o r F q . The difference i n numbers of observations, both within and among S_s must be taken into account. JLR, 2 f o r example, showed more s i g n i f i c a n t Hotelling's T tests and more s i g n i f i c a n t regressions than the others, but these may have resulted i n part from the fac t that there were twice as many utterances recorded f o r her. As can be seen i n Tables 3.4 - 3 . 9 , there were, i n f a c t , few examples of some of the context contrasts. Those results which were s i g n i f i c a n t f o r 2 the Hotelling's T tests should only be considered as implic-atory f o r future research i n this area. With respect to the regressions on age, the greater number of observations f o r the l a t e r sets of data may have influenced the slope and sign-i f i c a n c e thereof. 4 .2. Correspondence of the present analysis with previous  findings 4 . 2 1 . Duration In the present study, i t was found that the means of duration ranged from approximately 200 msec at 5 weeks to be-tween 400-700 msec at 16 weeks. These values agree generally with those reported previously by Murai ( i960) and Sheppard and Lane (1968) although Murai noted that a non-crying utter-ance at 6 weeks had a duration of 400 msec. Both the a r i t h -136 metic and geometric means were calculated i n Sheppard and Lane's study, the former being 5 5 0 msec and the l a t t e r 2 9 0 msec. Nakazima ( 1 9 6 2 ) noted i n a general way that the duration of utterances increased with age. The present findings i n d i c -ate that duration increased exponentially from at least 5 to 1 6 weeks f o r f i v e of the six Ss, although at d i f f e r e n t rate for each S_ (cf. Figure 3 . 1 ) . Sheppard and Lane found that duration f i r s t decreased from b i r t h to 3 weeks and the i n c r -eased continuously u n t i l 5 months (cf. Table 4 . 1 ) . The early decrease might have been due to the number of longer crying utterances i n the f i r s t few weeks, since i t was noted i n Ringel and Kluppel ( 1 9 6 4 ) study that the mean duration of a neonatal cry was approximately 1 . 5 seconds. Insert Table 4 . 1 about here In s t a t i n g from the present findings that duration i n c r -eases exponentially with age, i t i s implied that the amount of v a r i a t i o n , as well as the mean, increases with age, as the data indeed show; the SD increased from ca. 1 0 0 msec at 5 weeks to 5 0 0 msec at l6 weeks. On the other hand, Sheppard and Lane, c a l c u l a t i n g the c o e f f i c i e n t of v a r i a t i o n , found that i t decreased with age. Since the c o e f f i c i e n t of v a r i a t i o n was not determined i n the current study, i t cannot at the present TABLE 4.1. COMPARISON OF PRESENT FINDINGS FOR DURATION AND FUNDAMENTAL FREQUENCY WITH SHEPPARD g LANE (1968) Study Acoustic feature Subj ect Birth 21 days 45 days 137 days Sheppard and Lane (1968) Fundamental frequency Female 401 Hz 384 Hz 420 Hz 420 Hz Male ' 438 Hz 411 Hz 455 Hz 455 Hz Present study CAB (F) - - 341 Hz 425 Hz AMG (F) - - 382 Hz -JLR (F) AMR (M) - - - -DAE (M) - - 347 Hz -MJK (M) - - - -Sheppard and Lane (1968) Duration (msec) Arithmetic mean Female 1130 409 881 492 Male 613 466 327 623 Geometric mean Female 432 165 293 304 Male 267 229 179 342 Present study Arithmetic mean CAB (F) - 220 560 AMG CF) - 290 -JLR CF) - 440 -AMR (M) - - -DAE (M) - 364 -MJK (M) — — — (Based on Sheppard and Lane, 1968, pp. 102-103) 138 time be d e f i n i t i v e l y s t a t e d that the two f i n d i n g s do not concur. Furthermore, s i n c e both c r i e s and n o n - c r i e s were i n -c l u d e d i n the Sheppard and Lane study, the decrease i n number of the l o n g e r c r i e s over age may have e f f e c t e d a decrease i n the c o e f f i c i e n t of v a r i a t i o n . T h i s i s not to say that c r i e s and n o n - c r i e s are mutually e x c l u s i v e , f o r i n R i n g e l and K l u p p e l ' s study of c r i e s o n l y , a s m a l l i n t e r - s u b j e c t v a r i a b i l i t y was r e p o r t e d f o r d u r a t i o n . Although f o r the present study of non-c r i e s , a t e s t of the s l o p e s of r e g r e s s i o n on age i n d i c a t e d t h a t d u r a t i o n i n c r e a s e a t a d i f f e r e n t r a t e f o r each s u b j e c t , there appeared to be l e s s i n t e r - s u b j e c t v a r i a b i l i t y f o r d u r a t i o n than f o r o t h e r f e a t u r e s a n a l y z e d . 4 . 2 2 . Fundamental frequency In the l i t e r a t u r e review, i t was e v i d e n t that few s t u d i e s of n o n - c r y i n g u t t e r a n c e s have been c a r r i e d out. Those r e p o r t e d do not i n c l u d e s u f f i c i e n t data f o r comparison w i t h the present f i n d i n g s . L y n i p (1951) noted i n c i d e n t a l l y t h a t n o n - c r y i n g u t t e r a n c e s at 8 and 9 weeks had F^ at 360 and 420 Hz, r e s p e c t -i v e l y , b o t h values b e i n g w i t h i n the range noted f o r t h i s study ( c f . Appendix E ) . The data of Sheppard and Lane, a l t h o u g h of both c r i e s and n o n - c r i e s i s d i s c u s s e d here as one set of v a l u e s by which to assess the present ones. In t h e i r study, the over-a l l means up to 5 months f o r t h e i r two Ss were 443 Hz and 4 l 4 Hz, whereas i n the present study, most of the means were l e s s than 400 Hz. Sheppard and Lane a l s o r e p o r t e d an i n i t i a l decrease 139 i n F from b i r t h to 3 weeks followed by a progressive increase o which s t a b i l i z e d at about 8 weeks (cf. Table 4.1). This trend i s not supported by the current findings, i n which regressions for the means of F Q vary from subject to subject, both i n sign-i f i c a n c e and d i r e c t i o n . S i g n i f i c a n t regressions f o r B-P, M-P, and E-P i n the present study were negative, i n d i c a t i n g that F decreased with age f o r each of these points. Between- and within-utterance v a r i a t i o n was measured i n both present study and i n that of Sheppard and Lane. Between-utterance v a r i a t i o n was reported by Sheppard and Lane to be constant over age at 40 Hz (two-thirds of the points within 10% of the mean). This value i s not e n t i r e l y discrepant with that of the present study i n which there was v a r i a t i o n from ca. 25-100 Hz with a unimodality at 40 Hz. Within-utterance v a r i a t i o n as measured by the c o e f f i c i e n t of v a r i a t i o n Sheppard and Lane again noted to be constant at ko Hz. In the current study, v a r i a t i o n was measured by range ( i . e . , the difference between maximum and minimum F ). For f i v e out of six Ss, mean o — 3 range varied s i g n i f i c a n t l y over age — f o r four of these, i n a p o s i t i v e d i r e c t i o n . Furthermore, the variances of these mean ranges were not homogeneous among Ss. Since d i f f e r e n t measures of within-utterance v a r i a t i o n are used, the two findings cannot be f a i r l y or leg i t i m a t e l y contrasted. 140 In summary, i t appears that the differences i n the methodologies f o r the current study and that of Sheppard and Lane (1968) may y i e l d f a r less s i m i l a r results f o r F Q than f o r duration. With respect to the F Q-contour of infant utterances, comparisons can be drawn with Lieberman (1967) and Wasz-HSckert et a l . ( 1 9 6 8 ) . Lieberman claimed that f o r infants, as f o r adults, at the end of most utterances F Q f a l l s , because of reduced sub-glottal pressure and general relaxation of the vocal f o l d s . From a q u a l i t a t i v e appraisal of the present data, t h i s view appears to be supported, as would be expected i n l i g h t of the Kim (1968) review. The r i s i n g - f a l l i n g pattern of most pleasure signals reported by Wasz-Hflckert and his colleagues i s also supported by the present f i n d i n g s . 4 . 2 3 . Context contrasts of utterances ( H o t e l l i n g s 1 s T 2 tests) Several authors have stated that an infant communicates through the medium of intonation, a prosodic feature of speech. Kaplan, (1970) reported that caridac v a r i a b i l i t y increased when infants as young as k months were exposed to a sudden switch between adult male and female recorded voices, which suggested that the infants had perceived the d i f f e r e n c e . Lieberman (1967) claimed that two infants of 10 and 13 months of age accommodated t h e i r mean F Q to correspond to that of t h e i r father or mother. Rough imit a t i o n of the 'intonational pattern of the speaker's i n t e r j e c t i o n or expression of d e l i g h t ' 141 at k months was noted by Berry (1969); Weir (1966) had expressed a s i m i l a r observation. In the present study, the infan t s ' F^ i n d i f f e r e n t s i t -uations was compared by Hotelling's T 2 t e s t s , The l e v e l of s i g n i f i c a n c e was reached i n 15 out of 80 tests and appeared to be neither random fo r age nor f o r §_t 10 of the s i g n i f -icant contrasts were f o r JLR and these as early as 7 weeks, compared with at least 10 weeks fo r the others. It appears from these results that infants of a c e r t a i n developmental age are capable of responding by v a r i a t i o n i n F Q to changes i n s i t u a t i o n or v i s u a l stimulation, but that they do not do so c o n s i s t e n t l y . The present findings do not, then, d e f i n i t -i v e l y confirm nor refute those of Kaplan ( 1 9 7 0 ) , Berry ( 1 9 6 9 ) , and Weir ( 1 9 6 6 ) , although they confirm the need f o r future i n v e s t i g a t i o n of this aspect of infant behaviour. The kind of a l t e r a t i o n of F was not consistent i n a l l o contexts. However, contrary to Lieberman's (1967) claim, i t can be noted that infants up to k months of age did not accommodate t h e i r F q to correspond more c l o s e l y with that of an adult male vs an adult female. Certain a l t e r a t i o n s were made which could be related to the observations of White (1971) that by 4 months infants have a highly developed v i s u a l awareness — and of Kagan (1970) — that perception of a moderately novel stimulus may res u l t i n heightened motor 142 a c t i v i t y . In s i g n i f i c a n t contrasts to S_ x S+O, a greater mean with in-ut terance range often accounted for the d i f f e r e n c e , which suggests that an object qua novel or f a m i l i a r stimulus may have e l i c i t e d a general ly more var ied utterance . S i m i l a r l y , when the contexts of S+>1 x S+F and S+M x S+E were contrasted, the greater within-utterance range, as wel l as the greater mean maximum F , were noted for the contexts S+F and S+E, o i r r e s p e c t i v e of the sex of the a d u l t . Since both JE and the fathers were general ly less f a m i l i a r to the c h i l d than his mother, the second adult may have acted as a novel stimulus which induced heightened motor a c t i v i t y i n the form of more var ied and higher-pi tched utterances . However, th i s trend remains ambiguous, s ince the only a l t e r a t i o n common to con-tras t s between S_ and S+A was the occurrence of the mean min-imum F i n the group S+A. In th i s case, the adult qua novel stimulus may have induced a lowering of motor a c t i v i t y . S u b j e c t i v e l y , i t was noted by the author that adult speech or the in troduct ion of a new object caused at times a cess-a t i o n of v o c a l i z a t i o n ; th is observation might re la te to the f indings of Turnure (1971) that the presentat ion of a recorded adult voice resu l ted i n general motor qu ie t ing of the i n f a n t s . The d i f f i c u l t y i n c l a r i f y i n g th is issue from the present re su l t s r e f l e c t s the controversy i n studies of infant percep-t i o n discussed i n Chapter 1: i . e . , what const i tutes a response to a stimulus — motor a c t i v i t y , motor qu ie t ing or mere change i n motor a c t i v i t y . 143 4 . 3 . Relation of perceptual and biographical data to quanti-ta t i v e findings 4 . 3 1 . Outstanding subject In the sample of six S s, JLR was outstanding both i n amount of v o c a l i z a t i o n and numbers of tests which reached the l e v e l of s i g n i f i c a n c e . A consideration of c e r t a i n biographical data may c l a r i f y this s i t u a t i o n . On the f i r s t Bayley test at 3 . 5 months, JLR was the only S to perform above her age l e v e l , reaching a 5 month l e v e l on psychomotor tasks and a 4 -month l e v e l on mental development tasks (cf. lable 2 . 2 ) . Moreover, her environment was notably stimulating from the point of view of s o c i a l i n t e r a c t i o n , p a r t i c u l a r l y with her parents. These factors undoubtedly enhanced her development, and made i t possible f o r her to perform at a more advanced l e v e l than the other Ss. One might a t t r i b u t e the vocal responsiveness to environment as an outcome of her advanced development. 4 . 3 2 . Discussion of s p e c i f i c f i n d ings . As noted i n Chapter 3» Ss d i f f e r e d generally i n amount of v o c a l i z a t i o n . Whereas JLR produced the greatest number of utterances, CAB produced the least, r e l a t i v e l y speaking. Since CAB developed at a slower pace, as measured by the Bayley 144 Scales of Infant Development (1969). It i s conceivable that such effected a d i s i n c l i n a t i o n to v o c a l i z e . In none of the tests performed, were resu l t s s i g n i f i c a n t for a l l Ss, although several comparisons y ie lded s i g n i f i c a n t re su l t s for four or f i ve of the s ix Ss. One such example was the exponential increase i n durat ion for a l l S but MJK. Since MJK was the infant with greatest b ir thweight , i t could be postulated that he was p h y s i c a l l y capable of producing" utterances of more var ied and longer durations at an e a r l i e r age than the other Ss. However, this remains unclear , since the h ighly s t imulat ing environment of MJK may also have i n -fluenced th i s behaviour. A fur ther test of durat ion — the Students* t - t e s t f or utterances with one vd two M-P - - y i e lded s i g n i f i c a n t resu l t s for a l l but CAB, and indicated that utterances with two M-P were genera l ly longer. For CAB, i t must be noted that there were only nine examples of utterances with two M-P, compared with 187 with one M-P; i n th is case, the small number of observations may not be representat ive of CAB's general be-haviour . Since CAB was i n fact a p i l o t subject , i t could also be that measurement techniques were not h ighly ref ined at the time the spectrograms were measured; i . e . , the resu l t s may have been biased by measurement e r r o r . A t h i r d instance where s i gn i f i cance was obtained for a l l but 145 one B was range, i . e . , almost monotone (cf . Table 2.9). Sub-j e c t i v e l y , i t was noted by E that her behaviour appeared to r e f l e c t a general comfort s tate , expressed i n a rambling mon-ologue. JLR was not unique i n th is respect , but the abundance of monotone voca l i za t ions more s trongly re inforces the subject ive impression of contentment. Inter-subject v a r i a b i l i t y was noteworthy from other points of view for regress ion of range; for example, four s i g n i f i c a n t regressions were pos i t i ve i n s lope, i n d i c a t i n g an increase i n range with age, but for DAE, range decreased s i g n i f i c a n t l y with age. As noted i n Table 2.10, DAE made a great number of 'squealing* sounds during ear ly recordings , i n which there were large g l ides i n p i t c h ; there could only be in terpreted as vocal experimentations. The others squealed a l s o , but r e l a t i v e -ly seldom, compared with DAE. In two fur ther tests of range DAE d i f f e r e d from the other Ss. A t - t e s t comparison of range for utterances with one vs two M-P revealed that for DAE only , range was independent of the number of M-P (or f l u c t u a t i o n ) i n the utterance . In a regress ion of range on durat ion for utterances with two M-P, i t was evident that range was also independent of durat ion . However, i n utterances with one M-P DAE was s i m i l a r to other Ss, where range was a funct ion of d u r a t i o n . These resu l t s may r e f l e c t the vocal experimentation i n the ear ly recordings mentioned above. 146 The i n t e r a c t i o n of duration and range revealed other inter-subject v a r i a b i l i t y ; MJK and AMG demonstrated incon-sistency i n this regard. For MJK, range was a function of duration only i n utterances with two M-P, whereas the reverse was true f o r AMG. These results add another dimension to infant vocal production. Although infants generally demon-strated the dependency of frequency range on f l u c t u a t i o n and duration of the utterance, i t i s also apparent that such a r e l a t i o n s h i p i s not a necessary one. Why MJK, DAE, and AMG should have been d i f f e r e n t i s not immediately evident from biographical data. In tests of F Q, there was much inter-subject v a r i a b i l i t y . These regressions of F on age which were s i g n i f i c a n t were not o necessarily of the same measured point. However, the slope of these s i g n i f i c a n t regressions was negative f o r a l l Ss but CAB. There are several possible explanations f o r t h i s d i f f -erence; (1) CAB produced more higher-pitched laughs and squ-eals on the l a t e r recording; (2) there were fewer data points spread over a greater number of recordings, ( i . e . , the data may not be t r u l y representative of her vocal behaviour); and (3) CAB was developmentally slower than the others and may not have produced as t y p i c a l a pattern. Once again, there i s a notable contrast between CAB and JLR, the most advanced in f a n t . The other major group of tests involving F Q was the 2 H o t e l l i n g ^ T tests of utterances i n d i f f e r e n t contexts, f o r 147 which most s i g n i f i c a n t contrasts were noted f o r JLR and f o r which none were s i g n i f i c a n t f o r AMG. Possible reasons f o r JLR's sup e r i o r i t y have been discussed. Since only 6 out of 80 tests were performed fo r AMG, lack of data may have accounted f o r non-significant results obtained. Certain s i m i l a r i t i e s among Ss which have implications f o r infant s o c i a l behaviour can be found from a r e l a t i o n of amount of v o c a l i z a t i o n , context contrasts, and biographical data•. CAB: No p a r t i c u l a r biographical information appears to account f o r recording-to-recording v a r i a b i l i t y i n amount of v o c a l i z -ation i n the context of S+A, S or S+0. The recording at 18 weeks i s of special i n t e r e s t since i t consists almost e n t i r e l y of squeals uttered while f i x a t e d on her variegated blanket. Hotelling's T 2 test of S+O x S+M revealed no difference i n F Q and affirmed a subjective impression that, at least according to F , CAB did not s h i f t her attention from inanimate but color-o f u l object to an animate object. The same was true at l6 and 22 weeks f o r the contrasts of S+M x S+O. The f a c t that a f t e r 14- weeks, there were more vocalizations i n context of an object, may also r e f l e c t a growing awareness of her immediate physical environment. AMG; This subject vocalized more frequently alone than with an adult. The recording at 7 weeks showed p a r t i c u l a r l y that, when l e f t alone i n her c r i b with i t s mobile, she vocalized 148 almost continuously. Her behaviour i n this regard appears to be s i m i l a r to that of CAB mentioned above. JLR: Compared with the other children, JLR vocalized much more i n the context of an object. As a r e s u l t , Hotelling's T 2 tests more often revealed a s i g n i f i c a n t difference between utterances of S vs S+O than S vs S+A. Furthermore, there was generally less adult intervention i n her recording sessions than i n those f o r the other f i v e . These two facts could be related by the hypothesis put forward by Jones and Moss (1971) that infants who are extremely vocal do not e l i c i t as much maternal speech as quieter infants, since t h e i r vocalizations do not serve as novel s t i m u l i f o r the mother. The inverse, could also be i n f e r r e d from the present findings with respect to the mother-child i n t e r a c t i o n of AMR, the d e s c r i p t i o n of which follows t AMRt Very few vocalizations were recorded f o r AMR i n the early weeks and these were, fo r the most part, i n context of his mother. It was noted i n Table 2.8 that AMR * s mother was very t a l k a t i v e on these recordings, so much so that she often spoke over the c h i l d . When, f o r the f i n a l recording session of the s e r i e s , i t was decided to leave the c h i l d alone i n his c r i b with i t s mobile, there was a tremendous increase i n amount of v o c a l i z a t i o n . This was probably due i n part to maturation, but i t reinforces the theory that early vocal behaviour i s not necessarily s o c i a l , but egocentric. 1 4 9 DAEi No trends were evident i n the context contrasts f o r DAE MJK: On the early recordings, vocal behaviour seemed to be egocentric. Adult speech tended to induce smile responses i n -stead of the desired vocal response (cf. Table 2.11). However, on the l a t e r recordings, p a r t i c u l a r l y at l6 weeks, the infant responded voc a l l y and frequently to maternal speech. Develop-mental or as yet undetermined s o c i a l factors may have influenced th i s change. 4.4. Implications f o r theory and future research 4.4l. Produc t i o n The data c o l l e c t e d was of the infants' vocal production i n t h e i r natural environment from the age of 5-l6 weeks. Conse-quently, most t h e o r e t i c a l implications concern th i s aspect of the communication process. Of a l l the acoustic features of vocalizations examined i n the present study, duration appeared to y i e l d the most con-s i s t e n t r e s u l t s among Ss. For f i v e of the six chi l d r e n , i t i n -creased exponentially with age. Anatomical and ph y s i o l o g i c a l development probably influenced this phenomenon; as the c h i l d ' s vocal t r a c t and l i n g u i s t i c capacity develops, he becomes capable of sustaining longer non-crying utterances. Constraints of an anatomical and physiological nature probably account also f o r the differences i n duration of utterances with one M-P and two M-P 150 as well as for s i g n i f i c a n t regressions of within-utterance range on duration. Within a longer utterance, the c h i l d has more opportunity to vary the fundamental frequency (F Q) contour, both i n amount of f l u c t u a t i o n (number of M-P) and range. An exponential increase i n duration implies further that with age the c h i l d produces utterances more varied i n duration. Again, physical growth probably plays a role i n e f f e c t i n g this change, but the change may also r e f l e c t a growing capacity f o r and in t e r e s t i n phonatory experimentation, as discussed by Fry (1966) and Berry (1969). More precise p h y s i o l o g i c a l and anat-omical data would provide a measure by which to separate i n part p h y s i o l o g i c a l from psychological f a c t o r s . Experimentation could also generally account f o r the v a r i a b i l i t y i n the various aspects of F analyzed. The present data indicate that there o are no notable trends f o r development of F Q, at least according to B-P, M-P, and E-P. Compared to duration, FQ i s r e l a t i v e l y unrestrained with respect to anatomical and ph y s i o l o g i c a l constraints. Exceptions are shown possibly by: (1) the t-tests of within-utterance range f o r utterances with one and two M-P, i n that utterances with more f l u c t u a t i o n also have a greater within-utterance range; and (2) the f a l l i n g F -contours, which o may be related to the 'breath-group' hypothesis of Lieberman (1967) , but, i n any case, i s probably due to a relaxation of vocal folds and reduced sub-glottal pressure. A more extensive analysis of F Q-contour than was possible i n the confines of this study, along with anatomical and physiological data might further elucidate this issue. 151 Generally, however, a c h i l d i s capable of v o c a l i z i n g over a wide frequency range, DAE and CAB, for example, during c e r t a i n recording sessions, used high-pitched squeals to express themselves, although this was not a common mode of expression during other sessions. More often than the others, JLR vocal-ized i n a low-pitched montone, yet she was capable of a l t e r i n g that kind of expression when the s i t u a t i o n changed ( i . e . , l6 weeks, changing from a monotone while i n her c r i b watching mobiles, to a highly varied production while on the table being changed.) The increase i n within-utterance range with age f o r four of the six S_s further supports the hypothesis that with age the capacity f o r experimentation develops, the c h i l d becoming capable of producing a wide range of frequencies within the bounds of one expiration. h,k2, Production and perception: Context contrasts Utterances were categorized according to context and studied i n two ways: (a) according to amount of v o c a l i z a t i o n i n contexts S, S+A, and S+O (Figure 3.11 - 3.l6), and (2) Hotelling's T 2 tests of context contrasts (Tables J.k - 3.9). It generally appeared from the f i r s t study that c h i l d r e n vocalized more often in the contexts S and S+O than i n the context S+A. This suggests that much of early vocal production i s egocentric behaviour and/or r e f l e c t s the infants perception of his immediate physical environment, i . e . , what he perceives v i s u a l l y and t a c t u a l l y . 152 Piaget's concept of early sensorimotor i n t e l l i g e n c e would appear to be supported from this observation. Furthermore, the large percentage (80) of non-significant contrasts for the Hotelling's T 2 tests would affirm that the c h i l d r e n do not often respond d i f f e r e n t l y by F Q to what they may or may not perceive as a change i n t h e i r s i t u a t i o n . However, the f a c t that there were s i g n i f i c a n t r e s u l t s at a l l , and p a r t i c u l a r l y f o r the most advanced S, JLR, that the c h i l d r e n could respond d i f f e r e n t l y by F to t h e i r environment on occasion. Their o response implies a l i n k between perception and vocal production. The kind of vocal production, as described i n Section 4.23, may be, i n f a c t , a mere heightening of motor a c t i v i t y upon perception of a novel stimulus. With the data a v a i l a b l e , i t i s not possible to speculate as to the modality of percep-t i o n which most influences the changein vocal production. However, the apparent perception-production l i n k may r e i n -force the theory that supra-segmental features are operative early i n the f i r s t year of l i f e as c a r r i e r s of information. 4.5» Summary Non-crying utterances of 5- to l6-week-old infants recorded i n t h e i r environments were analyzed spectrographically f o r fund-amental frequency (F Q) and duration. The three major analyses performed were: (regressions of acoustic features on age, (2) Relationship of F and duration, and (3) contrasts of the 153 c h i l d ' s vocalizations i n d i f f e r e n t contexts. Not a l l regressions of acoustic features on chronolog-i c a l age were s i g n i f i c a n t . Two s i g n i f i c a n t trends, however were: ( 1 ) the exponential increase of duration on age, and (2) the l i n e a r increase of within-utterance range on age. With chronological age as a basis f o r analysis, inter-subject v a r i a b i l i t y was noted even f o r these trends. Biographical and perceptual data are used q u a l i t a t i v e l y to suggest reasons f o r both i n t e r - and intra-subject v a r i a b i l i t y . Since develop-ment i s not a completely uniform process within and among chi l d r e n , and since each c h i l d ' s environment i s d i f f e r e n t , i t would follow that developmental and s o c i a l data provide a firmer basis f o r analysis than chronological age. The r e s u l t that c h i l d r e n of the same chronological age vocalized d i f f e r -ently simply by number of utterances further supports the need f o r quantitative developmental and s o c i a l data as c r i t e r i a f o r ana l y s i s . The i n t e r a c t i o n of F q and duration showed generally that frequency range was dependent on f l u c t u a t i o n and duration of utterance. A more complex analysis of the F -contour than o can be provided spectrographically might y i e l d more information about this i n t e r a c t i o n , p a r t i c u l a r l y given data from childr e n of the same developmental age. 154 The c h i l d ' s vocal i n t e r a c t i o n with his environment was studied both q u a l i t a t i v e l y and q u a n t i t a t i v e l y . A frequency count of the number of utterances i n d i f f e r e n t contexts revealed that most ch i l d r e n vocalized more alone or with an object than with a person. 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A scale of infant psycholog ica l development. Unpublished manuscript, 1 9 6 4 . Vet ter , H. J . & Howell, R. W. Theories of language a c q u i s i t i o n . Journal of Psycho l lngu i s t i c Research, 1 9 7 1 , 1. (1) , 31 -64 . Vuorenkoski, V . , L i n d , J . , Wasz-Hflckert, 0 . , & Partanen, T . J . Cry Score: A method for evaluat ing the degree of abnormal-i t y i n the pain cry response of the newborn and young i n f a n t . Speech Transmission Laboratory Quarter ly Progress and Status Report, 1 9 7 1 , 6 8 - 7 5 . Wasz-HcJckert, 0. , L i n d , J . , Vuorenkoski, V . , Partanen, T. , & Valanne, E . The infant c r y . A spectrographic and auditory  a n a l y s i s . Lavenham, Suffo lk: Spastics In ternat iona l Medical P u b l i c a t i o n in as soc ia t ion with Wil l iam Heinemann Medical Books L t d . , 1968. 161 Weir, R. Some questions on the c h i l d ' s l earn ing of phonology. In F . Smith and G. A. M i l l e r (Eds . ) , The genesis of language. A psycho l ingu i s t i c approach. Cambridge, Mass. : The M. I . T. Press , 1966. Weisberg, P. Soc ia l and nonsocial cond i t ion ing of infant v o c a l i z a t i o n s . C h i l d Development, 1963, 3ji, 377-338. White, B . L . Human Infants . Experience and psycholog ica l development. Engelwood C l i f f s , N. J . : P r e n t i c e - H a l l , Inc. 1971. W i n i t z , H. Spectrographic i n v e s t i g a t i o n of infant vowels. The Journal of Genetic Psychology, i960, 96, 171-181. W i n i t z , H. A r t i c u l a t o r y a c q u i s i t i o n and behaviour. New York: Apple ton-Century-Crof t s , 1969. APPENDIX A INTRA-OBSERVER RELIABILITY FOR FUNDAMENTAL FREQUENCY: BEGINNING-POINT (CAB) -1 -2 316 Hz. 326 Hz. 300 298 344 352 364 366 310 312 356 356 284 288 198 204 474 466 338 338 126 124 446 470 382 382 544 560 478 492 242 240 376 376 410" 404 350 352 6638 6706 ANALYSIS OF VARIANCE Source ss df MS F Between utterances 121.68 1 121.68 0.01 Within utterances 3.6895xl05 36 10,249. Total 3.6907xl05 37 162 APPENDIX B LINEAR REGRESSIONS OF LOG OF DURATION ON AGE e (y = e ) y = Loge of duration Ccsec), x = Age (wks) The following figures represent xerox reductions of computer print-out. At the top of each figure are listed the constant a, the coefficient b, and the F-probability. The "."and "*" are used to plot the regression lines, "*" being used when a plot point covers data points. Integers (I) represent approximately 2 x1 data points; 0 represents 1 or no data points; A represents 20 or more data points. I f 'D-01' follows any number in the printout, that number must be divided by ten. Figure B.l: CAB Figure B.2: AMG Figure B.3: AMR Figure B.4: JLR Figure B.5: DAE Figure B.6: MJK 163 rigure B . l . Regression of Log a of Duration.on Ago: GAB T.CP " I M ) 'CONST CO Cr F F K A T I o " " FPR.0B STU I'RR ' STD FPR " ' S T C ERR ~ " RSO VAR VAR A B ( P ) ( H I ( A ) (F< I ( Y ) IOG OUR AGE 2 . 7 9 5 O.^ebD-Ol 2 2 . 33 C.0O0P 0 . 1 5 9 1 0 . 1 0 3 2 C - 0 1 C . 7 0 6 0 n . 1 0 7 3 THE « . » AND • • * " ARE USEC TC PLOT THE RECK ESS ION L I N E ; THE " • " I S USED WHEN A HLCT P C I M CCVERS DA TA POINTS 5 . 7 0 C 1.900 2.1 C O 1 . 2 0 miiiiiinn / J/////J/I mi III I\I \IIII ii ii i\ \i i III 111\ n\i inn \n II i\ui i A IIIM miiiSi i II ni II in 5. C C - ) 7 8 H . « C " ) 1 0 1 1 . 8 0 m 1 5 . 2 0 1 6 1 8 1 8 . 6 0 2 0 2 2 . C I S T A N C C B E T W E E N S L A S H E S ( I N T H C X - A X I S I S C . 1 7 0 0 C D x = AGE (wks) _ _ F i g u r e B . 2 . ^ R e g r e s s i o n o i _ L o g _ o f D u r a t i o n o n A g e : AM3 O E P I NO C C N S T C O E F F ' " F K A T I O F P R G O " S T O E ' R ST C EH R S T C EPR R SO V A R V A R A B ( R ) ( R ) ( A > { H ) ( Y ) L C G O I H A C F 2 . 5 2 4 C . 7 7 0 7 0 - 0 1 4 1 . 4 3 C . O O O f ) 0 . 1 3 9 0 0 . 1 1 S 7 D - C 1 C . 7 2 A 8 1 6 1 f t T H E " . " A N O " • " A R E U S E D TO- P L O T THE R E G R E S S I O N L I N E : T H E I S U S E D W H F N A PL TT F C I NT . C X V E R S D A T A P O I N T S A N I N T E G E R " I " , B E T W E E N 1 ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 2 * 1 C A T A P O I N T S _ » 0 " R E P R E S E N T S 1 OR FEWER D A T A P O I N T S ; " A " R E P R E S E N T S 2 0 OR MORE D A T A P O I N T S  5 . 1 0 0 - 0 • f - . K V / y = 2 . 5 2 4 + 0 . 0 7 7 0 2 X 0 0 o ' . ' 3 1 4 . o u r ! 4 . S O " . ! 4 . s ? r 4 . 7 5 ! > 0 o c r* r-4 . 6 * 1 t . t K ! / 1 3 r. 4 . A 7 : ; 1 1 C n r. 4. 4 r c j 4..->->: / 0 1 4 . ? A i . i 1 3 I 1 4. 1 i 4 . 1 2 ' ; <>. / 0 I 0 / 0 I 0 1 0 •» c 3 . OK"- ! 8 3 . 7 0 C / 3 - 0 4 0 1 0 1 2 . 1 • 2 3 . J 4'"> ? . 77.- i 3 . 7 . - C ; / 3 . 0 3 " ; z / I l 0 1 M / 3 . 4 o r / 1 2 0 l c 2 3 .4?i" 3 . 3«r-o o / 0 4 0 0 2 3 . 2 F . " ' 3.14.'. 3 . " 7'-. • 3 . C 0 0 >> - 0 . 5 3 2 1 1 i . r nr 2 . ' - ) 3 r I 2 . 2 . 7 9 - ' / 1 4 0 0 1 2 . 7 2 0 ; 2 . 3 2 . * IC-! 2 . 4 4 ^ 2.37:^ 2 . 3 0 0 - 1 5 2 3 2 . 3 : r ! 2 . 2 3 1 ', I ' . l f r - " 2 . " d o ; / 2 . - V 1 / l . = » f ' " ' ', i . ? i -/ 1 . 7 4 .• i 1 . - - 7 ' 1 . 6 C 0 - 1 3 f l 0 • i/\//ii/////\//////i\/\ //////i//\i//n\///\/i/////n\ II mini\iiitiiIInii IIIIIIn i/i/II in 5 . 0 0 0 7 7 . 2 0 0 9 9 . 4 C 0 1 1 . 6 0 1 3 . 8 . ' D I S T A N C E B E T W E E N S L A S H E S ON T F E X - A X I S I S n . 1 i o n illll/lll/\ 1 5 1 6 . 1 . 6 C C x = AGE (wks) or P i w VAR VAR LOGCUR AGE THE AND C CN S T A 1 .991 " APF USED Figure B.3. Regression of U>£L of Duration oh Age CnFfF fKAI IC fPHOn STD B'R B (r l) (B) (A) 0.1208 £2 .57 O.i'iOOn 0. 2UH2 Tfl PLOT THC REGRESSION LINE; THF " » " IS USED WHEN AMR s i n rr<R " ~ "sTh YKR ( K I ( Y | 0. 15270-C1 C .7in; j A PLOT POINT C.OVFRS I .1 r'2C o<l[ NTS AN INTEGER "I",BETWEEN 1 ANO 9, REPRESENTS APPROXIMATELY " 0 " REPRE SENTS 1 OR FFV.ER DATA POINTS; " A " REPRESENTS 3*1 DATA POINTS 29 DP MORE DATA POINTS i 1 y = 1.991 + 0.1208X 0 1 r i 1 0 1 i 0 2 ; 4 .7C0 ; 3 2 1 0 1 i 1 < i 1 ', 1 3 3 0 4 2 ; a 0 0 2 1 1 3 3.900 ! fi 1 1 4 « •H 1 0 7 ; i 0 • «; < 0 1 0 3 l « 6 ! •/ ; ^ / 1 2 • 0 1 1 " 3 . 1 0 0 • ! >< j i / 1 4 2 1 6 1 / 1 l 2 2 3 j ' 2.300 - 1 l 1 2 2 i i i ', l 0 0 0 1 . 5 0 1 / / i ii ii ii 11 i\u i\ii 111 \ ii 111111 ni 111 ii 11 I\I i\u 111 ni 11 ti I\I I\I i n 1111 I\I 111 ii i n\i i ii i n 11 \ a a 11 a i\ S.OOn 9 9.400 10. 80 12 12.2C 13 .6 " 1*. DISTANCE BETWEEN SLASHES ON THE X-AXIS IS 0.7000E-01 ' . , ? t > f '>. 1 i>' r . 1 re 4 4 . i' (•: 4 . rK. 4 . 1 ? l ' . . • 3 ' . . 4 .4 t,. m l ' . . 3 ^ i . 4 . ? . ? . 4 .1 ' . ' ' 3 . I K ! 3 . 9 r r 1..-2C 3 . 7 4 ( ' «. r.r-A . ^ Hi * . v - i ' f 3. * ?f 3.341. •> . . '(.-!• 3 . I «••> 3 . •>. ''?<• 7. " 4 f 2 . " W v 2 . 7 H " 2 . 70,-" '?.('?••• 2 . S 4 . 2. 4 of . ' . 3 0 2 . 3Of .-.??'• 2.1 4 f " 2. ^60 1 . 1 1 T ' 1 . ' V K 1. « 2 ' 1 . 7 4 0 t . '-r . 1 . «• !)••• 1 . 5 Of CD CO x = AGE (wks) C C " I M ) VAR V AH L O G O U R AGO T H E " AN I N T E G E R " 0 " RE PRE 5 . 3 0 C 4 . 5 0 0 3 . 7 0 0 Q O 2 . 9 0 0 2 . 1 0 0 F i g u r e B . ' l . R e g r e s s i o n o f L o g g o f D u r a t i o n o n A g e : J L R C O N S T "CYIEVE F R A T I f ) ' FOR On " ~ S T 0 fc'RR~ S I [T F ' » p " ' S 'T ITFRR A B I B ) I B ) <A» ( B ) t Y ) 3 . 1 4 2 0 . 2 3 6 7 0 - 0 1 7 . 3 4 5 1 . 1 ( 1 6 9 0 . 1 0 0 0 0 . 9 7 3 5 C - 0 2 C . . 7 3 4 0 NO • • • » ARE U S E C TO P L O T THE R E C E S S I O N L I N E : THE « * » I S U S E D WHEN A P L C T P C I N T C E V F P S OAT A " I " , B E T W E E N 1 AND 0 , R E P R E S E N T S A P P R O X I M A T E L Y 3 * 1 CATA P O I N T S ENTS 1 OR FEWER DATA P O I N T S ; " A " R E P R E S E N T S 2 9 OR MORF OA TA P O I N T S 0 y = 3 . W 2 + 0 . 0 2 3 6 7 x 1 0 0 F S O 1 . 1 1 3 4 PC I NTS 1 . 3 0 0 i t\i 111 IIIII\II II 111\i \ 11 IIIIII I\IIII i\ii/t\ti IIII 11 I\I 111 IIII t\i 11111 ti I\III i it 11 i\\iit 11 m \ it n ti tin 5 . I C O 7 7 . 2 0 0 9 9 . 4 0 1 " - 1 1 . 6 0 1 3 . 9 ) l h . D I S T A N C E B E T W E E N S L A S H E S ON THE X - A X I S I S 0 . 1 1 0 3 5 . i . 2 2'' '-.1 4.' • ' 6 ' 4 . i: ji i 4 i 4 . » 2 ' ' . . 7 40 4 .(•*:. 4 . 4 . 26 . 4 . M -4 . 1 1 , ' '•.<?/ \ . o 4* 3 . t ' 6 i • 3 . 7 B ' > , 7 V 1. 6 ' " ' 3 . f . 4 i 3 . 4 6 " 3 . 3 S;'" 3.3.''' 3.22^ 3 . 1 4.; 3.: 6 3 •>. 'J V 2. 1 2 .74 ' 2. . - A ' 2. i i " ' 2 • * ' V 3. 4 ? " 3 . 2*>r 2. 1 <r 2. 1 •> -i ( >r» 1 . Q 4 ' ' 1 . 3 6l 1 . 7 S ' 1. 7 2 " l.'.2<" I . * 4-1.46 ^ 1.3*3 1 . V I cn X = AGE ( w k s ) F i g u r e B . 5 . R e g r e s s i o n o f l o g o f D u r a t i o n o n A g e : DAE _ C F P I r:0 C O N S T " " C O EFT ' F P . A T I O H ' R n n " " ST I ) l 'RR ST 11 ERR ' " " " S T C F.PR RSC V » U VAP A R I B ) ( 0 ) ( A ) I K ) ( Y ) L n r . r . i j P A C t 2 . T 4 0 . 0 . 5 < ) r . 6 n - C l 1 7 . «3 7 C . O O O l O . 1 H 0 0 0 . 1 4 0 S C - C I O.tPh'i C . 0 R 6 8 T K - " . " AND ' • « " ARE I I S F H T O PLOT T H F R E G R E S S I O N L I N E ; THE " * " I S L S F P WHEN A P L C T P C I C T C C V F R S D A T A P O I N T S 5 . 2 < - 0 4 . 4 C 0 5 3 ' . * C 0 g " 2 . i o n >4 . 2 . C C O y » 2 . 9 t 9 + 0 . 0 5 9 5 6 x 1 . 2 0 0 //1 ii ii m 111 ii ii ii I\I i\ ii III in i \ in minx in i\ i in i n mm i \mi 11 n /1 n\i u i i i M i m i III\ mini n i 5 . ' 1 0 0 7 7 . 2 ( 0 o . t f t n i o 1 1 . A O 1 3 1 3 . 8 0 ) ( . , . P . ? S T A N C F : J B F J WEEN. _S LA SHE S . .0N JHLJt AX L L J . S . _ C . l . I C O *i . 1 ?>•• S . ">4 0 4 . 0 6 0 4.H:»J 4. HO''' " 4 . 7 2 0 4 . 6 4 0 4 . ^ 0 4 . 4 i r -4 . o r . 4 . 3 ? " 4 . 2 4 C 4 . 1 6 0 4. 0 31 4 . P " . ' I 3 . " 2 0 » . f > 4 0 " 3.76<-' 3 . r , S O 3 . 6 0 1 3 . 2 0 3,440 3 . 3 6 0 3 . 2 0 : ' 3.20T 3 . 1 2 0 3 . 0 4 0 2 . ih: ' 2 . H - V 2 . 7 ? o 2 . ' . 4 r 2 . 5 6 0 2 . 4H0 2 . 4 0 0 2 . )?o 2 . 2 4 0 7. 1 (-0 2 . 0 HO 2 . 0 0 0 1 . o 20 1 .*40 1 . 7 6 0 1 . 6 R 0 1 . * o r 1 . " 0 1 . 4 4 0 ' " " I . 3 « C " 1 . 2*0 1 . 2 0 0 r o cn oo x = AGE ( w k s ) E i g u r e B . 6 . R e g r e s s i o n o f L o g o f D u r a t i o n o n A g e : MJK or. p i c r r HP IHf- " A f j P I T " 5 . U C /r, r 3 . 2 ^ 5 Akt- LSF.C COEFF " -FUATIO F i - p n i t l> I P ) ( H) o.i', u u ) - r i ].<.••. 7 c.2 1 0 1 ) K P I O T U i F R I G I ' I S S I CN I. I N F ; T h f " » " 3*1 " . r U T W F F N 1 A NO 0 . I t f P I ' F J E M < A P P R O X I M A T E L Y S 1 HP EF.WFR f.A T A P O I N T S ^ " A " R FPP F S T N T S y = 3.255 + 0.01W.6X STO F K R 5 1 0 FRR STO ERR i A i ( n ) i Y i 0 . 1 5 1 5 0 . 1 1 5 9 E - 0 1 0 . 7 0 6 8 I S U S F n WHEN A P L t l P C I M C O V E R S D A T A 0 A T A P O I N T S PSC 0 . 1 0 6 1 P O I N T S 2 9 DU MIIP.F D A T A P O I N T S 0 o i n 1 0 I\I i II 11111 \ n 11 II 111\ II 1111\ i I\I i II 11111 \ 111 I\I 11 I\II 111111 I\I 11\ 11 II i\i i\i II 11 I\I 11111 II ni 11111111\ 5 . n f ' i 7 . ? r o 8 9 . 4 0 0 IOC 1 1 . 6 0 1 3 1 3 . « 0 1 6 . S I A M C I ; ' i r i w F C I I S I . A I H I ' S CN T h E X - A X I S I S C l l C O 5 . 0 30 4 . '160 4 . <5'=0 4 . R 2 0 4 . 7r'0 4 , 6 P0 4 . 6 1 0 4 . ' .AO 4 . 4 70 4 . 4 0 0 4 . )1H 2 ' 0 4 . 1 •>-> 4 . 1 2 C 4 . 0^0 •3.«af 3.111 3. 1140 ' 3 . 770 3 . 7 0 0 3 . 6 3 0 3 . r . 6 C 3. 40A 3. 420 3. 3 5f 3. 2 10 3 . 2 1 0 3 . 1 4 0 3. f 70 3 . 0 00 2 . - H O 2 . ° 6 ( 2 . 7>51 2 . 720 2 . 6^0 2.">i,r 2 . 5 1 0 2 . 440 2 . 3 70 2 .3 00 2 . 2 30 ' 2 . 1 60• " .» . 390 2. 0 2 0 1 .''50 1 . 8 3 0 l . « I C 1 . 7 40 1 . 6 7 0 1 . 6 0 0 •30 CD CD x = AGE ( w k s ) APPENDIX C LOG OF DURATION AND WITHIN-UTTERANCE RANGE: e BARTLETT'S TEST FOR HOMDGENETTY OF VARIANCE When more than two independent estimates of variance exist, Bartlett's test for homogeneity of variance has been used (Snedecor and Cochran, 1967, pp. 296-298). For samples of different sizes, the following formula is applied: M = (log 10)[ (EfJlog s 2 - Efjlog s i 2 J where M = the test criterion log 10 = 2.3026 6e s2 = Ef.s.2/Ef. i i l f = size of sample s 2 = variance On the null hypothesis that each variance is a measure of the same a 2, the quantity M/C is distributed approximately as X2 with (a - 1) degrees of freedom, where a = the number of samples, and C = 1 + — [ E — - — J 3(a - 1) f. zf. l l In the present study, this statistic was utilized to test the variances of log e of duration and within-utterance range between children (cf. Sections 3.1 and 3.2). Details of these calculations folia-/ in Table C.l. 170 171 TABLE C.l BARTLETT'S TEST FOR HOMOGENEITY OF VARIANCE Sample M C df X 2 x2.95 x .9999 Log of duration &e 1.53750 1.00159 4 1.53506 9.488 Within-utterance 83.22807 1.00174 3 83.08315 21.108 range APPENDIX D STUDENT'S t-TESTS OF DURATION AND WITHIN-UTTERANCE RANGE FOR UTTERANCES WITH ONE AND TWO MIDDLE-POINTS Student's t-tests are used to test whether two means are significantly different (i.e., derive from different populations). As outlined in Sections 3.1 and 3.2 (pp. 89-107 )J o n e °f '^wo computer t-test routines was utilized to determine whether there was a significant difference between utterances with one M-P versus those with two, both for duration and within-utterance range: Formula (1) and Formula (3), as defined in Bjerring and Seagraves (1971, pp. 80-83). Formula (1) assumes only that the parent populations are normal. In Section 3.1, i t was noted that the t-value calculated is in fact t' as designated in Snedecor and Cochran (1967, pp. 114-116). (la) t f (lb) df (Xi - x2) s 2 -)-Mi M2 s i 2 + Mi 2 Mi + — M (Mi - 1) (M2 - 1) where M = number of obser-vations/sample X = mean of a sample s 2 - variance of a sample 172 173 For the t'-value deterimjied, a probability level must also be calculated, according to the following procedure: (lc) t l = W j t i + w2t2. 2- W i + W 2 where w = M ti = significance level for (Ma - 1) df t 2 - significance level for CM2 - 1) df TormuLa C3) represents a more sensitive version of the first formula and is used when populations are heterogeneic for variance. C3a). CXj ^ ^ 2 ^ t s (Mj - Ds-i2 + (M2 - D s 2 2 Mj + M2 - 2 M2 M2 C3B) df s Mj + M2 - 2 Duration Ccf. Section 3.1) Tor al l Ss but DAE, Formula Cl) was used to compare the means of duration of utterances with one and two M-P, A full example of the calculation is presented helow: CAB Cla) .. 3^.2086 - 101.111 _ 5 7 < 9 0 1 1 + t' =" 1(39.6778)2 4- C83.3583)2 187 9 2.073 27.9372 174 (lb) df = K39.6778) 2 4- (83.3583)2 ' 2 L 187 r 9 J "(39.6778) 2 2 (83.3583) 2 ' 2 187 J L 9 186 8 609158.5523 74511.3706 8.1754 = 8 (lc) t'-probability at the .05 level t i = 2.576 t 2 = 3.355 (39.6778) 2 (83.3583) 2 „ „ „ n c „ Q  w_ = W 2 = _ / /2 .06/3 187 9 t i = [ (8.4188) (2 .576) : + [(772.0673) (3.355)] . _ 3 3 1 | 6 5 • 0 5 (8.4188) + (772.0673) Since t ' i s less than the calculated probability, the populations are not significantly different. For the Ss AMG, AMR, JLR, and MJK, calculation of t 1 i s provided below: A M _ [(3.2314) (3 .291) ] + [(57.6841) (3 .883)1 _ _ AMG: t ' n n 1 = d.bblb • - (3.2314) + (57.6841) A v m + i [ (3.2987) (3 .291) ] + [(16.1598) (3 .460) ] _ o U 1 o AMR: t ' n n , = • d..H_Lcs • U U 1 (3.2987) + (16.1598) JLR. t ' = [ (1.1344) (3.291) ] + [(20.1572) (3 .460) ] = 3 U Q 2 .001 MJK* t ' X .001 (1.1344) + (20.1572) [ (2.6678) (3 .291) ] + [C26.5593) (3 .55DJ _ 3 5 2 ? 3 (2.6678) + (26.5593) Calculation of t for HAE hys'Forxnula, 13)_ i s as. follows. (3a) t = — 45.4790 - 89.5833 = _ 5 > 8 7 1 2 ;Q66) (33.4341) 2 ] + [(.23) (40.7782) 2 ] 167 + 24 ^ 2 167 24 175 (3b) df = 167 + 24 - 2 = 189 £ < .001. Within-utterance range (cf. Section 3.2) For DAE only, Formula (1) was u t i l i z e d to analyze the difference i n means for utterances with one vs two M-P with respect to within-utterance range. DAE: (la) (lb) 122.31 - 125.41 V = 3.10 df 74.7901)2 24 (140.415)2 + _(74.790)2 24 18.7382 = 0.165 E (140.415)2 167 (74.790)2 24 166 23 = 110649.1317 = 50.4116 2445.662 = 50 (lc) t ' probability at the .05 ..level t i = 1.98 w2 = ( l l f 0-. 4 1 5 ) 2 = 118.0621 167 t , = 2.069 (74 790) 2  W 2 = w t . / a u ; •= 233.0650 24 t' C(018.0621) CI.98) + 1(233.0650) (2.069)3 = 2,4544 "05 C118.0621) + C233.0650) Thus, the samples are not significantly different. One example of a Formula (3) calculation for within-utterance range i s as follows: CAB: (3a) t = • 8 7 - 6 8 9 8 . - V 1 5 " - 8 . 8 9 • . : =2.305 rT(187 - 1) (86.0356)2] + [(9 - 1) (69.1094)2] 187 + 9 - 2 (3b) df = 187 + 9 - 2 = 194 2- + i -187 Hence, p_ < .05 APPENDIX E FUNDAMENTAL FREQUENCY: MEANS AND STANDARD DEVIATIONS FOR BEGINNING-POINT, MIDDLE-POINT, END-POINT, AND DERIVED MEANS TABLE E.l TABLE E.2 TABLE E.3 TABLE E.4 Beginnixig-Point Middle-Point End-Point Derived Means 176 TABLE E.l: BEGINNING-POINT (All values to nearest Hz ) Subject Item 5 7 8 9 10 Age 11 (in weeks) 12 13 14 15 16 18 20 22 CAB Mean 328 322 323 - 359 - 363 333 — 386 687 5 360 SD 0 27 41 - 105 - 67 66 - 68 262 51 82 AMG Mean 409 357 - 400 - - 383 - 368 382 - - -SD 35 62 - 64 - - 65 - 67 85 - - -AMR Mean _a _a 347 341 - 382 355 ' - - 342 - - - -SD - - 65 52 - 55 82 - 64 - - - -JLR Mean 393 400 352 - - - 330 - 348 - - -SD 84 113 - 78 - - - 60 - 166 - - -DAE Mean 319 334 - - 507 - 406 - - 373 - - -SD 67 79 - - 158 - 160 - - 99 - - -MJK Mean 330 - 428 - 344 - 326 329 - - 323 - - -SD 65 - 246 - 119 - 43 110 - - 91 - - -Note: Except as noted, missing values indicated no recording session at age designated. For number of observations (N) for each child at each age level, refer to Table 3.1. a Recording made, but no viable utterances produced. TABLE E.2: MIDDLE-POINT (All values to nearest Hz ) Subject Item 5 7 8 9 10 Age 11 (in weeks) 12 13 14 15 16 18 20 22 CAB Mean 314 352 332 _ 383 — 380 373 — 441 716 442 413 SD 0 31 40 - 93 - 41 27 - 88 264 54- 85 AMG Mean 427 407 - 401 - - 393 - 402 421 - - -SD 34 64 - 48 - - 59 - 61 87 - - -AMR Mean _a _a 356 369 - 372 366 - 339 - - - -SD - - 71 52 - 47 87 - 67 - - - -JLR Mean 411 419 - 337 - - - 324 - 352 - - -SD 88 128 - 79 - - - 70 - 100 - - -DAE Mean 341 377 - - 623 - 459 - - 382 - - -SD 70 161 - - 229 - 220 - - 87 - - -MJK Mean 359 - 442 - 366 - 351 401 - - 362 - - -SD 54 — 224 — 103 — 71 183 — — 74 — — — Note: Except as noted, missing values indicated no recording session at age designated. For number of observations (N) for each child at each age level, refer to Table 3.1 a Recording made, but no viable utterances produced. TABLE E.3: END-POINT (All values to nearest Hz) Subject Item 5 7 8 9 10 Age 11 (in weeks) 12 13 14 15 16 18 20 22 CAB Mean 264 338 317 . 355 365 327 391 595 357 320 SD 0 23 48 97 - 44 51 - 92 168 99 59 AMG Mean 391 365 - 381 - - 348 - 310 372 - - -SD 51 69 - 35 - - 55 - 61 91 - - -AMR Mean _a _a 332 314 - 347 344 - ; - 331 - - - -SD - - 91 68 - 49 84 - 52 - - - -JLR Mean 357 384 - 326 - - - 312 - 310 - -SD 75 101 - 53 - - - 57 - 57 - - -DAE Mean 303 336 - '- 501 - 407 - - 355 - - -SD 36 99 - - 164 - 170 - - 82 - - -MJK Mean 333 - 350 - 329 - 306 344 - - 300 - - -SD 37 - 94 - - 96 64 165 - 72 - - -Note: Unless otherwise indicated, missing values represent times.when recordings were not made. For number of observations (N) for each child at each age level, refer to Table 3.1. a Recording made, but no viable utterances produced. TABLE E.4: DERIVED MEANS (All values to nearest Hz ) Subject Item 5 7 8 9 10 Age 11 (in weeks) 12 13 14 15 16 18 20 22 CAB Mean 302 341 324 — 369 — 372 351 _ 413 680 425 375 SD 0 13 38 - 94 - 40 32 - 71 218 56 65 AMG Mean 413 •382 - 396 . - - 379 - 366 397 - - -SD 33 55 - 46 - - 49 - 53 75 - - -AMR Mean 347 348 - 368 356 - 341 - - - -SD - - 66 49 - 46 77 - 43 - - - -JLR Mean 392 407 - 339 - - - 323 - 342 - - -SD 76 91 - 62 - - - 51 - 87 - - -DAE Mean 326 356 - - 546 - 433 - - 374 - - -SD 61 116 - - 163 - 184 - - 78 - - -MJK Mean 345 - 415 - 348 - 330 366 - - 335 - -SD 45 — 183 86 — 41 151 — — 64 — — Note: Except as noted, missing values indicated no recording session at age designated. For number of observations (N) for each child at each age level, refer to Table 3.1. a Recording made, but no viable utterances produced. APPENDIX F LINEAR REGRESSIONS OF FUNDAMENTAL FREQUENCY ON AGE y = a + bx y = Fundamental frequency (Hz), x = Age (wks) The following figures represent xerox reductions of computer print-out. At the top of each figure are l i s t e d the constant, a, the coefficient b, and the F-probability. The "." and "*" are used to plot the regression lines, """ being used when a plot point covers data points. Integers (I) represent approximately 2 x 1 data points; 0 represents 1 or no data points; A represents 20 or more data points. For each S_, regressions of beginning-point, middle-point, and end-point as well as the derived mean are plotted. Figures F . l - F.4: CAB Figures F.5 - F.8: AMG Figures F.9 - F.12: AMR Figures F.13 - F.16: JLR Figures F.17 - F.20: DAE Figures F.21 - F.24: MJK 181 nr p i N O V » 0 V AP B E G I N AGE THE " . " A N O « « ' R S U F i g u r e F . l . R e g r e s s i o n o f B o g i n n i i i g - P c d n t o n A g o : CAB C C N S T " " " c r i r F F " F R A T I C ~ F P i ' O B " j T O E K K S T F I F P R STO ERR A B I B ) I B ) ( A l ( B ) ( Y ) 2 9 8 . 9 . ft.003 . 9 . 5 4 6 C . 0 0 2 5 2 9 . 9 5 1 . 9 4 3 1 3 2 . 9 0 . 1 4 6 9 ' A R t L S E O TO PLOT THE R E G R E S S I C N L I N E ; THE ' • * " I S USEO WHEN A P L O T P O I N T C O V E R S O A T A P O I N T S 1 2 4 0 . 1 0 2 0 . 5 G 0 . O t, 5 H C . 0 ' 3 6 0 . 0 y " 298.9 + 6.003x 1 4 0 . 0 / / i / / / / / / / / / 1 /I mi I\I 11 II i in i\i II ilium \UIIIIII\II\IIIIII M 11At 11nn n AnI\I11111An aII inin 5 . 0 0 1 7 8 8.400 la 11.80 m 15.20 16 18 18.60 20 22, D I S T A N C E B E T W E E N S L A S H E S CN THE X - A X I S I S 0.1700 1 2 4 0 . 1 2 1 P . 1 1 9 6 . 1 I 7 4 . 1 1 1 2 . _ 1 1 3 0 . _ U C 3 . 1 0 8 6 . 1 0 6 4 . 1 0 4 2 . H 2 0 . 9 9 H . C " 9 7 6 . 0 ~ 9 * i 4 . 0 " 3 2 . C 9 1 0 . 0 8 8 8 . 0 _ 8 6 6 . 0 _ 8 4 4 . 0 B 2 2 . 0 BOO . 0 7 7 , 3 . 0 7 5 6 . 0 7 3 4 . 1 " 7 1 2 . ( • " 6 9 0 . 1 6 6 R . 0 6 4 6 . 0 6 2 4 . 0 _ 6 3 2 . 0 5 8 0 . 0 " 5 5 8 . 0 5 3 6 . 0 5 1 4 . 0 4O2 . 0 4 7 0 . 0 " 4 4 3 . 0 " " 4 2 6 . 0 4 0 4 . 0 3 H 2 . 0 3 6 0 . 0 3 3 8 .C " ' 3 1 6 . 0 " 2 9 4 . 0 2 7 2 . 0 2 5 0 . 0 2 2 8 . 0 2 0 6 . 0 " 1 8 4 . 0 * 1 6 2 . 0 1 4 0 . 0 0 0 I—' CO *••= AGE (wks) F i g u r e F . 2 . K e g r e o s i o n o f M i d d l e - P o i n t o n A p o : f ! A R KSO O C P I N D CONST C O E F F F K A T I O F P R O B STD FUR ST 0 ERR S T C ERR VAR VAR A R I R I ( B l < A ) ( B l » Y ) M I D AG F 2 1 8 . 7 P . 4 2 1 1 9 . 4 1 0 . 0 0 0 0 2 9 . 4 6 1 . 9 1 1 1 3 0 . 7 0 . 0 9 1 0 I F F " . " ANO " » • • ARE U S E C TO P L O T T h E R E G R E S S I O N L I N E ; THE " • " I S U S E D WHEN A P L C T P C I N T C C V E R S D A T A P O I N T S AN I N 1 F G E R " I " , B E T W E E N 1 ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 2 * 1 C A T A P O I N T S " 0 " R E P R E S E N T S 1 OR FEWER DATA P O I N T S ; " A " R E P R E S E N T S 2 0 OR MORE D A T A P O I N T S 1 2 8 C . - " " " 0 y = 2 9 8 . 7 • 8 . t 2 1 x 1 0 6 0 . f j 3 4 0 . 0 » 6 2 0 . 0 4 0 0 . 0 0 0 0 "l 7 3 1 2 1 1 0 - • — "o" 1 8 C . C //1 mi n III l A IUII\I I//////u\11 II i u in\\i II II in | 1A1//111 l inikiiii \u iiiSm l imiiAi l in i in II I 5 . 0 0 3 7 8 0 . 4 0 0 10 1 1 . 8 0 l" t 1 5 . 2 0 16 1 8 1 8 . 6 0 20 2 2 , . 0 1 SJANCE B E T W E E N S L A S H E S ON THE X - A X I S I S 0 . 1 7 0 0 '_ " " x ' AGE " ( w k s ) 1 2 * C . " ~ 1 2 5 8 . 1 2 3 6 . 1 2 1 4 . 1 1 " 2 . 1 1 7 0 . _ ~ i i « 8 . 1 1 2 6 . 1 1 0 4 . 1 0 H 2 . 1 0 6 0 . 1 0 3 R . ~ ' i 0 1 6 . " 9 9 4 . 0 9 Y 2 . 0 9 5 0 . 0 9 2 8 . 0 _ 9 0 6 . r . 8 8 4 . 6 ' 8 6 2 . 0 8 4 0 . 0 R l f t . C 7 9 6 . 0 7 7 4 . 0 " 7 5 2 . 0 ' 7 3 0 . 0 7 0 8 . 0 6 H 6 . 0 6 6 4 . 0 6 4 2 . 0 _ 6 2 0 . 0 59(1 . 0 S 76 .f. ' • 5 4 . 0 S 3 2 . 0 5 1 0 . 0 " ' 4 8 8 . 0 4 6 6 . 0 4 4 4 . 0 4 2 2 . 0 4 0 0 . 0 3 7 1 . 0 " 3 5 6 . 0 " 3 3 4 . 0 3 1 2 . 0 2 9 0 . 0 2 6 8 . 0 2 4 6 . 0 " 2 2 4 . 0 ' 2 0 2 . 0 1 8 0 . 0 0 0 I—1 CO CO F i g u r e F . 3 . R e g r e s s i o n o f E n d - p o i n t o n A g e : CAB C l ' P I N D C C N S T ™ C . F . F F " " F R AT I r ) F P R O B S T D FRR " $ T D ' r ' P B ~ S T C FRR RSC "\. V A ° VAK A B I B ) I H ) ( A ) I B ) I Y ) f N U AC F 3 3 2 . 0 2 . 5 1 7 2 . 4 3 5 0 . 1 1 6 O 2 4 . 8 7 1 . 6 1 3 1 1 0 . 3 0 . 0 1 2 4 THF » . « A N : ARE U S E C T O PLOT T H E R E G R E S S I O N L I N E : THE » * " I S USED WHEN A P L C T P C I M C C V E R S OATA P O I N T S 9 1 3 . 0 7 6 0 . 0 U 6 1 9 . 0 3 1 0 . 0 y 3 3 2 . 0 + 2 . 5 1 7 x 1 6 0 . 0 9 1 0 . 0 8 9 5 . 0 3 R C . 8 6 5 . 310. 8 3 5 . 8 2 0 H 0 5 . 7 9 0 . 0 7 71 .0 7 6 0 . 0 7 4 5 .0 ~ 7 3 f ) . 0 ~ 71 5 . 0 7 . 0 . 0 6 8 5 . 0 6 7 0 . 0 ( . « . 0 " " 6 4 0 . r ' 6 2 5 . 0 6 10 . 0 5 9 5 . 0 18 3 .0 5 6 5 . 0 5 5 0 . 0 ' 5 3 5 . 0 5 2 0 . 0 5 0 1 . 0 4 9 0 . 0 471.0 " 4 6 0 . 0 " ' 4 4 S . 0 4 3 3 . r 4 1 5 . 0 4 0 1 . p 38S . O " "3 7 n . l>~ 3 5 5 . 0 3 4 O . 0 3 2 5 . 0 3 1 0 . 0 2 9 5 . 0 " 2 8 0 . 0 " 2 6 5 . 0 2 5 0 . 0 2 3 5 . 0 2 2 " . 0 //111 ii ii i ii I \ iIIIIAI1 ii 11 ii iik ii 11 ii n 11 ii ii 11 nhiiiii i iinhiii1 ii ii ih in 11 II n i \i i / / / / / / / / / i 5 . 0 0 0 7 8 8 . 4 0 0 10 1 1 . 8 0 W 1 5 . 2 0 16 1 8 1 8 . 6 0 20 2 2 , 0 1 STANCE H F 7 V f EN S L A S H E S (JN THE X - A X I S I S 0 . 1 7 C O 2 0 5 , 1 9 0 . 1 7 5 , 1 6 0 . 0 0 CD x = AGE ( w k s ) Figure F.<4. Regression of frnn f Q on Age> C A B _ . _ Of P ' 1 »:6 " C C N C T " " ~ " "COFFF F R I H c " FPP.I'B ST D F k R * ST 6 FRP.'" STD FRR VAR V A R A n (B) (Rl (Al (B I (Yl ME AN F ACf 3 0 5 . 2 6 . 3 9 2 1 3 . 6 4 0 . 0 0 0 4 2 6 . 6 8 1 . 7 2 1 1 1 8 . 4 Tt-E ••.» AND " • " AftF LSFC TO PLOT THF REGRESSION LIME; THF ••*•• IS USED WHFN A PI DT POINT COVERS DATA AN INTEGER "I", BETWEEN 1 AN 0 9 , REPRESENTS APPROXIMATELY 2 « I DATA POINTS " C " REPRESENTS 1 OR FEWER DATA PCINTS; " A " REPRESENTS 2 0 OR MORE DATA POINTS  1 1 3 0 . - ""* " " 0 / y = 3 0 5 . 2 + 6 . 3 9 2 X / / /_ / / / / 0 RSO 0.0657 POINTS 943 . 7 5 0 . C 370.0 / ' / " I I I I _ / • / / / / _ / / / / / / . / / / / / / / / / / / _ _ 1 / 1 / / 0 / / / _ _ _ _ _ _ _ _ _ _ _ / i I\I i II 111 i II \ 1111111 11 ill i 11 II u 1111 I\I i n\i II i\i 111/\n i\i i in 11\ 5.0C- 7 8 8 .400 3.0 11.80 I t 15.20 16 18 18. 60 20 CI STANCE BETWEEN SLASHFS UN THE X-AXIS IS 0.1 700 _ _ _ _ _ _ " x = AGE (wks) " 0 0 0 2 0 1 * 0 * 1 0 1 1 1 3 1 0 3 0 1 1 i\n 11111 in 22. 1 1 3 0 . 1 1 1 1 . 1 0 ^ 2 . 1 D 7 3 . 1 0 5 4 ; 1 0 . -4 . " 1 0 1 6 . " 9 9 7 . 0 9 7 8 . 0 0 S Q . fl 9 4 0 .C _ ° 2 l 9 0 2 . f " 8t» 3 .u 8 6 4 .0 t)4 5. 0 "."•6 . 0 «r>7 . 0 " " 7 8 8 . O'" 769 . 0 7 C 0 . 0 7 3 1 .C 7 1 2 .C 6 9 3 . r 6 7 4 . 0 " 65"> . r 6 3 6 .0 6 1 7 . 0 5 ° a . o 5 7 9 . 1 5 f O . 0 5 4 1 . 0 5 2 2 . 0 503.0 4 8 4 . 0 4 6 S . 0 4 4 6 . 0 4 2 7 . 0 4 0 , 4 . ( 1 3 8 9 . 0 3 7 0 . 0 3 5 1 . 0 ' 3 3 2 . 0 3 1 3 . 0 2 9 4 . 0 2 7 5.0 2 5 6 . 0 2 3 7 . 0 " 2 1 8 . 0 " 1 9 9 . 0 1 8 0 . 0 0 0 CO Cn D F P V A R B E G I N THE I NO V AP AGE ' . « ANO C C N S T A 3 6 7 . 1 « * " ARE U S E D F i g u r e F . 5 , CFIEFF F l ' A T I C fl ( B l 0 . 5 8 B 9 0 . 2 7 0 7 R e g r e s s i o n o f B e g i n n i n g - P o i n t o n A g e : AMG_ F P K I I B ""' ~~ST0 F P R S T I ) I PR ( B l ( A l ( B l 0 . 6 C 9 R 1 3 . 2 4 1 . 1 3 2 STO F F R I Y I 6 F . 7 6 TO P L O T T H E R E G R E S S 1CN L I N F : T H E " * " I S U S E D WHFN A P L O T P O I N T C O V F R S D A T A RSO 0 . 0 0 1 3 P O I N T S 2 1 0 . 0 i m i ii ii 11 i\u 11 ii i\n 5 . 0 0 0 7 7 0 1 STANCE B E T W E E N 111111111 \ 11111\111 \ 111111111 \ 111111111 \ l 11\11111 \ 111111111 \ 111111111 ]\ 11111111 \ . 2 0 0 9 9 . 4 0 0 1 1 . 6 0 1 3 . H O 1 5 1 6 . S L A S H E S ON THE X - A X I S I S 0 . 1 1 0 0 CD CT) x a AGE ( w k s ) OFP VAR M I D D L E T r E I N D V A R AGE CONST A 4 C 7 . 2 CO FEE fl C . 1 2 7 0 F i g u r e F . 6 . R e g r e s s i o n o f M i d d l e - P o i n t o n A g e : AMG F P A T in F P P f l l ) STO ' DR~p" ST r~ FRS ST~f:"l :PT" ( P . ) ( H ) ( A ) (11) ( V ) 0 . 1 3 4 4 D - 0 1 0 . S 7 4 1 1 2 . R l 1 . 0 5 5 6 6 . 5 3 0 . 0 0 0 1 "Yeo.6" 6 7 0 . 0 5 6 C . 0 „ 4 5 0 . 0 3 4 0 . 0 2 3 0 . 0 ANO • ' * " ARE U S E C TO P L O T THE R E G R E S S I O N L I N F ; THF « « » I S USFF) WHCN A P L C T PC I NT COVFRS OAT A P C I N T S / - 7 r tr . i S 1 1 y = t 0 7 . 2 + 0 . 1 2 7 0 X 1 76 9 . 0 ! 1  r< i>. ."' ' 1 7 4 7 . f , 1 736 .C 1 7 ? i . (' 1 7 1 4 . ( 1 7 " 3 . r j 1 1 6 H l . ( - 6 7 1 . 0 1 1 1 c . . ' 1 1 6 3 7.1 ! 1 1 6 2 ' . . <• 1 6 1 •'• .0 1 1 6 r - 4 . ' ' 1 R 9 ? . 0 1 1 5M? . ( 1 « 71 ."• - 5 6 , . C - i 1 1 1 1 3 4 > « . 0 1 1 1 5 ? 7 . r 1 ' 1 1 r - 1 6 . :• / 2 3 5! ^ . 0 / 1 1 4 - 1 4 . 0 1 2 1 2 4 H 3 . 0 1 1 3 1 1 4 7 2 . T / 1 5 2 1 4'-l . •• - i — " 2 2 3 "4 5,1. / 2 5 1 1 2 4 3 9., ' ' i / 1 6 1 1 1 4 ' : l . • / 5 5 3 3 7 1 4 1 7 , r / « 2 1 2 4',o." ; / 1 9 3 7 3 IV 2 2 5 9 1 7 2 2 3 1 373 . ' ' 1 6 1 3 2 3 6 ? . C 1 1 /, 1 1 3 M . ' - 5 1 1 1 i 34-i.,- ; 1 2 2 4 1 12 9 . o 1 " ' 3 "31.-i.l- ". / 2 I 3 , 1 7 . . -1 2 1 2 9 6 . 0 j / 1 2 S 5 . C 1 1 ?''-. . ' ' 1 ? 6 3 . i 1 ? 5 ? . 0 1 1 ?4 1 .1 _ "* 3 • ( 1l\l1IIIIIII [I1IIIIl\l\II1111II71 iiuilim 111 /11111 \ 11 /111111 \ 11A11111 \ 111111111 \ i 11111111 \ \ 1111 II 11 \ 5. 0 C 0 7 7 . 2 0 0 9 9 . 4 0 0 1 1 . 6 0 1 3 . BO 1 5 1 6 . ' i CO —J CISTANCC BETWEEN SLASHES CN THE X-AXIS IS 0 . 1 1 C 0 x = AGE (wks) Figure F . 7 . Regression of End-Point on Age: AMG C E P inn C O N S T coc rF F R A T I O F I > R O B V A R V A R A B l e i < R 1 E N D A G E 3 8 9 . 1 - 2 . 9 7 8 6 . 1 4 7 T F E A N D • ' » » A R E U S F O ' T O P L O T T H E R E G R E S S I O N L I N E l. S.J STO FRR S T O I: R P S I T. FFR I A ) ( f l l ( V ) C . H 3 4 1 3 . 8 1 1 . 1 P I 7 1 . 7 4 " . - > 2 7 8 THE ' " « " I S USED WHEN A P L C T P O I N T CCVERS D A T A P O I N T S A N I N T E G E P " I " , B E T W E E N 1 A N O 9 , R E P R E S E N T S A P P R O X I M A T F L Y " O " R E P R E S E N T S 1 O R F E W E R D A T A P O I N T S ; " A " R E P R E S E N T S " 7 - C . C " - " 2 « I C A T A P O I N T S 2 0 O R M O R E D A T A P O I N T S 6 6 C . 0 £ 5 * 0 . 0 4 . 0 . 0 3 0 0 . 0 1 £ 0 . 0 / y = 3 8 9 . 1 - 2 . 9 2 8 X / / / _ / " / / / / / \ ~~l / / / / / / / / / " / / / / / _ / / / / / / 'I / / / / " / / / / / / « I " " / - 0 . inunuunuiiiii\i\iiiiiiiii\iiiii\iii\iiiiiiiii\iiiiiiiii\ii\iiiii\inuiiii\iiiiiiiiiwiiuiiii\ 5 . 1 0 0 7 7 . 2 0 0 9 9 . 4 0 0 11 . 6 ' 1 3 . « " 15 I l. D I S T A N C E B E T W E E N S L A S H E S ON T H E X - A X I S I S O . l l C O 7 K . r It •>.< 7 4 4 . 0 7 3 2 . 1 72. ' . . ' » : * . : ' " o°6.l ' ?4 .1 6 72 . '• 6 6 2 . ( 64 H .•-6 3 6 . '•" 6 2 4 . 0 61 2 . 0 !.1'0 . •• 5 K 3 . 0 , 576 . 1 -5 5 2 . 0 ••40 .0 5 2 * . ' ' 5 1 6 . 5'."4 . ! 4 f:. o 4 - A . O 456 . r 4 4 4, 0 4 1 ^ ~*> i.C 1 ° / > . t 3H4 .C 372.c ••... _ ' 3 <• .1 . •'• ?3*.0 3 2 4 .0 313. ; 3 1 - O . O 2 q * •'" 2 7 o . ( ' 2 6 4 . r 25 7 .0 24. ' . f 223.1 21t>.''< "?•: 4 . T ' 1°2.< M'" .o co oo x a AGE ( w k s ) F i g u r e F . 8 . R e g r e s s i o n o f Mean F Q o n A g e : AMG CFP I N 0 VAR V A R MEAN F AGE I F F AND AN I N T E G E R " I " 0 " R E P R E S E N T S 6 E C . C C O N S T CO FF F F P A T I O F P R f l B STO ERR A B ( 0 ) I B ) ( A ) 3 9 2 . 7 - C . 7 0 5 7 0 . 5 3 7 0 0 . 4 7 1 1 1 1 . 2 6 " * " ARE U S E C Tt) P L O T THE R E G R E S S I O N L I N E ; THE " • • ' I S USED WHEN • i B E T W E F N 1 ANO 9 , R E P R E S E N T S A P P R C X I M A T FL Y 2 * 1 CATA P O I N T S F <(J ST 0 FPR S T C FRR (11) ( V 1 0 . 9 6 3 0 - 6 . 5 C U . O C 2 5 A PL CT P O I N T C C V E P S OAT A P f ' I N T S 1 OR FEWER OATA P O I N T S ; " A " R E P R E S E N T S 2 0 OR MORF OATA P O I N T S 5 9 0 . 0 6 r\ 5 0 0 . 0 » 4 1 0 . 0 3 2 0 . 0 y = 3 9 2 . 7 - 7 . 0 5 7 x 6 6 M 6- 6 2 (•« r 4 4 ' 31 " n 2 r M ' i" Q O • 1 5 9 ' S 7? ".•.fa * 2 7 5 13 « . ; n 5,' -4 91 4 1_ 4 7.' 4 4 5 4 4 46 43 7 42 : 1 4 19 " 4 t . 4.'1 39 2 1 S3 174 ' 6 5 " l 5 h 3 4 7 3 2 ° 3?'-311 " i O ? 2 ° 3 2-14 2 75 264 - 4 7 2 " -i 2 <9 2 3 0 . C / / i n u 1111 i\u 11 ii i\/i HI HI in i a iihm 1111111111 \ 111111111 \i 11\11111 \ 111111111 \ 11111111 n li uium 5 . 0 0 0 7 7 . 2 0 0 9 9 . 4 0 0 11 . 6 0 1 2 1 3 . H O 1 5 1 6 . 01 STANCE BE TWEEN S L A S H E S ON T H E X - A X I S I S 0 . 1 1 0 0 _ x = AGE ( w k s ) DE P | NI) VAK VAP B E C I . > AGE THF " . " AND AN I N T E G E t " F SC F i g u r e F . 9 . R e g r e s s i o n o f J e g i n n i n g - P o i n t o n A g e : AMR CONST " ' C r j - F F ™ ' " ' FPAT I1 I " F P P n r f " STD CRF " S T O ' C K R S l f ! ' F ' K R A B ( 0 ) I B ) ( A ) I H ) I Y ) 3 6 1 . 4 - 1 . 1 9 1 C . 7 6 1 5 0. 3 8 7 6 i e . 6 1 1 . 3 6 4 6 3 . 4 1 '. .C?2 • •»• • ARE L S E C TO PLOT T h E R F G K F S S l f \ L I N E ; THE " » " I S U S E D WHEN A P L C T P C I N T C T V F P S O A T A P O I N T S I " , B E T W E E N 1 ANC 9 , R E P R E S E N T S A P P R O X I M A T E L Y 3 * 1 D A T A P O I N T S " 0 " R E P R E S E N T S _ 5 5 0 . 0 " -1 OR FEWER D A T A P C I N T S ; " A " R E P R E S E N T S 2 9 OR MORE D A T A P O I N T S 4 7 C . 0 3 3 5 0 . 0 i 10 . 0 2 3 0 . 0 y = 3 6 1 . 1 - 1.191X 1 5 0 . 0 i I\I i in 11 n\ 11 hi 11111\ 111111111 \ 111111111 \ i K' 111111 \ 111111\11 \ 111111111 \ 111111111 \ 111111111 \ iiu nun 8 . 0 0 0 9 9 . 4 0 0 1 0 . 8 0 12 1 2 . 2 1 1 3 . 6 0 15 . D I S T A N C E B E T W E E N S L A S H E S CN THE X - A X I S I S 0 . 7 O O 0 E - O 1 * 4 ? . 4 3 4 . 5 26 . •:• 1j _M' 4 9^ , 4 " 6 . 4 7 , , 4 7 -4 f 2 '"4 V . 4 4 * . 4 , 4 2 2 . _ 4 1 4 " f 3 4 2 . 17-.. ? 4'' 3 4 2 . 31 * . "31 • 7'It* 2 7 " 2 6 2 . 2 5 4 . 2 4 ? , 2 3 . 3 . 2 «•" J ? ? 2 l"4 . 2 - 6 . 1 9 . 3 . 1 «!• ! . - I . - . 1 7 4 . "1 6r-. 1 4 3 . 1 4 V x = AGE ( w k s ) __ _ Figure F.10. Regression of Middle-Point on Age: AMR OEP IND "" ' C O N S T C C f C F F "" F K A T I C EPKOR STO EKK STO ERR ' STO FPR " " ' RSO VAR VAR A B ( HI ( B ) (A» ( B ) (Y) M IDOLE AGE 4 1 5 . 5 - 5 . 0 2 3 1 2 . 9 9 0 . 0 0 0 5 1 9 . 0 2 1 . 3 S 4 6 4 . H 4 n . . i 3 1 9 THE » . » AND "*•• ARE USED TO PLOT THE R E G R E S S I O N L I N E ; T HF " »•• IS USED WHEN A PL OT P O I N T C O V E R S DATA P O I N T S AN INTEGER " I " . B E T W E E N 1 ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 3*1 DATA P O I N T S " 0 " R E P R E S E N T S 1 OR FEWER CATA P C I N T S ; " A " R E P R E S E N T S 29 OR WIRE DATA P O I N T S 5 6 0 . 0 4 7 0 . 0 3 8 C . 0 " 2 5 0 . 0 2 0 0 . 0 1 1 0 . 0 / 7 V / / / / o / y = 115.5 - 5.023x / - — - - - -/ / / / / _ _ " / ' '"' ' • ' " " •- • - - - - - - - -/ i I\I i ii 1111 t\n h ii 111 \ ii ii ii ii i\n i n 111 n I\I 111111 \ n 1111\i m i n 1111 nu 1111 n i\mi I HI nn n mi n I n ' c 5 1 • •' 1 4 7 . 1 i 3 3 .' 1 24 .1 51 i . ri i 4<>7., 4 •<*. " 1 4 7" ..' 4 7 r t i l . ' 4'. 2.< 3 4 4 3 M . • ? 4 1 4 . ' " 1 421 .' 416.. 2 4'- r.. 3 '" io<., ; _ 3P'> . «; . r 7 371 . 1 -4 362 .1 4 3 ••••>.; * ) 4 4 . > 4 3 3r' .f 7 32' .' 3 M7.i t i . H .>' 7 2 ° J . ' ' c 2 ''•' .2 3 2 3i.': 2 2 7?..' 1 263.. 1 214 . 1 1 _ ~> 4 , 1 1 2 ,: t . i' 1 2 2 7 .r 1 2 1 H. 2 1 7'".<' 7 r .i 1 1^1 . 0 1F7 .C r 17 3.0 1 1 6 4 . . 1 r 1 5 1 . r r 1 4 6 . : 1 37., 12 3 . r ' l i o . r no.'' H-i CO B. ICO 9 9 . 4 0 0 01 STANCE BETWEEN S L A S H E S ON THE X - A X I S I S 1 0 . 8 0 C . 7 C C 0 F - O 1 11 1 2 . 20 1 3 . 60 1 5 . x = AGE (wks) F i g u r e F . l l . R e g r e s s i o n o f . E n d - P o i n t o n A g e : _ A M R C E P I ND CONST C O E F F F P A T I O F P R ' 1 0 STD r i ' P STD T K P ST 0 EPP PSO VAR VAN A n ( B I ( H I ( A I ( H I ( Y l END AGE 3 1 1 . 4 1 . 4 0 4 1 . 2 3 9 r . 2 6 5 6 1 7 . 2 0 1 . 2 6 1 5 F . 6 4 0 . 0 0 3 5 THE " . " AND " • « ARE USEC TO PLOT T H E R E G R E S S I O N L I N E ; THE • • * • ' I S USED WHEN A P L C T P C I N T C C V E R S OATA P O I N T S AN I N T E G E R " I " , B E T W E E N 1 AND 9 i R E P R E S E N T S A P P R O X I M A T E L Y 3 « I C A T A P O I N T S " 0 " R E P R E S E N T S 1 OR FEWER D A T A P O I N T S ; " A " R E P R E S E N T S 2 9 OH MORE D A T A P C I N T S  '5 7 0 . 0 " - - • - - - • (- - r < ' y = 3 1 1 . 4 + 1 .10MX r ' 6 2 . / 4 * 4 . / • .'.6. / 4 > » . / V',.'. •i S / 5 2 2 . / 4 1 4 . / S ' . / . / 0 4 > M . 4 9 0 . 0 - 4 « , - . / 0 J 4 " ? . / " ~ ~ " ' 0 " " " " ' • 7 - . / 0 0 4 6 6 . / 0 4 > > 1 . / 0 . / 0 0 C 4 4 2 . / o 4 > 4 . / 0 ~ ' ~ "1 ""<••>,: J I 0 " 4 1 " . 4 1 0 . 0 - 0 0 1 4 K . / 1 1 2 4 " ' . 9 / 0 ? 3 9 4 . >~ I _ 1 0 0 3 3 (• 4 . "_3' " " " / " ~ ' 0 1 3 ~ 7 » . fa / 1 1 0 6 .3 7 . £ / 0 1 5 3i. 2 . 3 / 1 7 1 6 4 . ^ / 2 0 • > • " • < • . I 1 0 0 4 3 3 0 . ' 3 3 0 . 0 " " - 1 ~ . 0 ' 3 ' . / . 1 1 0 3 •<?.?. / I I 3 3 | , . / 0 1 0 3 3 . - 6 . / 1 1 2 ? 9 * . / 1 1 0 ( ? « • • . / 1 ~ ~ 0 " —~C> 3" ' 2 - - 2 . / 1 1 5 2 7 4 . / 1 2 ? ' 6 . / 1 2 2 5 0 . 0 - 0 0 1 2 5 ^ . / 2 2 4 . ' . / ' 0 " ' " " ""• ' ' ' ' / 1 0 2 2 s . / 0 1 2 1 - . / 0 „ ! • ' . / 0 ( . ! . ' . / _ _ _ 0 '• / " " ~ "" " " ' ' " l ' i 6 V / 1 1 7 - » . 1 7 0 . 0 0 0 / / I / / / / / / / / / I / / / / / / / / / I / / / / / / / / / I nun 1111111111/1111/11 111111 m 11111111111 I\I 1111111 I\II 1111111\ B . 0 0 0 9 9 . 4 0 0 1 0 . 8 0 1 2 1 ? . ? 0 1 3 . 6 ' ' 1 5 . . ' ^ D I S T A N C E B E T W E E N _ S L A S H E S _ 0 N _ T H E X - M 1 S I S C . 7 0 < / ( ) . - 0 1 ; x = AGE ( w k s ) F i g u r e F . 1 2 . R e g r e s s i o n o f M e a n F o n A g o : AMR CONST ' " C O F P F ~ ' F P M I P FPF.OH STL) f 1<R A H I R ) I D ) ( A ) 3 6 8 . 6 - 1 . 7 8 8 3 . 0 8 0 1 . 0 7 6 3 1 3 . 9 0 " * • ' ARE U S E C T O PLOT THE P E O R C S S I O N L I N E ; THE ' • * " I S USED WHEN 3 * 1 OAT A P O I N T S 2 9 OR HORF OATA P O I N T S OEP 1 N 0 VAR VAR MEAN F AGE THE " . " ANO AN I N T E G f r " I " , B E T W E E N I ANO 9 , R E P R E S E N T S A P P R O X I MAT F LY " 0 ^ J < E P R J S E N T S 1 OR FEWER D A T A P O I N T S : " A " P E P R F SF NTS 5 2 0 . 0 " - ~ " ... / y = 3 6 8 . 8 - 1.788X / / / 0 / STI1 ERR ST C EPR I B 1 ( Y > 1 . 0 1 9 4 7 . 4 0 A P L C T P O I N T C C V E R S D A T A «S 0 o . o c e 7 P O I N T S 4 6 0 . 0 4 0 0 . 0 3 4 0 . f i " 2 8 0 . 0 2 2 0 . 0 / / / / / 0 "7'"o~ / 0 / / / 0 " T ~ 0 ~ I I I l l ii\iiiiiiiii\iihiiiiii\iiiiiiiii\iiiiiiiii\ii\iiiiii\iiiiii\ii\iiiiiiiii\iiiiiiiii\iiiiiiin\ II II in 11\ 8 . 0 0 0 9 9 . 4 0 0 1 0 . BO 12 12 . 2 0 1 3 . 6 0 1 5 . 0 1 STANCE B E T W E E N S L A S H E S CN THE X - A X I S I S 0 . 7 0 ' m E - O l r . 14 .< S r H . 1 ' 5 i ' 2 . 1 4 0 6 . 0 4 0 0 . 0 ' 4 3 4 . 0 " ' 4 7 8 . 0 4 72 .1 4 „ 6 . o 4 5 4 .I 4 4 X . 2* 4 4 2 . (' ' . 3 6 . 0 4 3 2 . 2 4 2 4 . 0 4 l 8 .I/ " 4 l 2 . " 4 1 6 . " 4 I ' ! .I' 3 9 4 . 0 3 8 8 . ^ 3 * 2 3 76 . 0 " 3 7o.C 3 6 4 . ( 3 5 * . C 3 5 2 . 0 _ 3 4r>.0 ( 4 - . ' . i.'." 3 1 4 . 0 32 l . l " 3 7 2 . 1 1 1 6 . 0 M... 3 1 4 . 0 ' 2 9 * . . ' -2 * 6 . i 2 8 0 . 0 2 7 4 . 0 2 6 * . 1 1 26 7 . C-2 5 6 . 0 2 C 7 . o 2 4 4 . 0 2 38 .( 2 3 2 . r ' 2 2 6 . 0 2 2 i . f LD CO x = AGE ( w k s ) V r Of- P VAR. B E G I N THE AN I _ - 0 " " 1 3 7 0 . _ . F i g u r e P . 1 3 , . R e g r e s s i o n o f . B e e i n n i n g - P o i n t a n A c e : . . J L R . . . . _ _ . . . . I NO CONST C O C F F F P . A T I O F P R O B S T i l f K R STO ERR S I C CRP VAR A B ( U l ( B l ( A l ( U l ( V I AGE 4 1 5 . 5 - 5 . 3 7 6 1 9 . 1 1 0 . 0 0 0 0 1 4 . O B l . ? 3 0 1 0 3 . 3 > . " AND APE L S E D TC PLOT T H E R E G R E S S I O N I I N F ; T HE " * " I S USFO WHEN A P L O T P O I N T C C V F K S RSO 0 . 0 3 4 2 P O I N T S N T C G E R " I " t B E T W E E N 1 ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y R E P R E S E N T S 3 OR FEWER D A T A P O I N T S ; " A " R E P R E S E N T S 6 * 1 C A T A P O I N T S 5 f i OR M I R E D A T A P O I N T S 1 5 3 0 . 1 1 9 0 . I 1 g_ » 6"50"7(T 5 1 0 . C 1 7 0 . 0 y o 1 1 S . S - 5 . 3 7 6 X 3 1 1 o i i\n ii III U\u 11 II iv n IImi IIi \ it 11 I\I i mi 1111111\ II II it II ni IIII i II n II 11 II 11 i\i\t in i II nii II i II II i 5 . 0 0 0 ' 7 . 2 0 0 9 9 . 4 0 0 1 1 . 6 0 1 3 . H O 1 6 . 0 1 ST ANCE BETWEEN S L A S H E S ON THE X - A X I S " I S 0 . 1 1 0 0 15 7 ' ' . I * < 6 . 1 S i ? . 1 7 ' j " . 1 7 1 7-'0. ' l 6 t - 6 . i n ; . 1 r* ^ H . 1 "•(>'.. 1 5 3 . 1 . 1 4>)6. " 1 4 . - 2 . " 1 1 1-4. ! 3t . . 1 3 : . , . i ' I i 224. 1 I K ' . 1 1 5 6 . 1 I2 2 . 1 "•*•>. i •: ."" 1 ••. ' i l>6.0 912 1 1 * . ' . 8 * 4 . 0 .0™ 8 1 " 7 a 2 . 0 748 . 1 7 i 4 . i-6-1 ".<• 5 4 6 . . " ' 6 1 2 ...i 5 7.3. 0 544 . 0 r- 1 4 7 6 . ' -442 .f 4 08 . 0 3 7-. . 1 3 4 •> .<• J •"..<• 2 7 2 . " 2 1c 2 C 4 . 0 1 7 0 . ' CD -F X = AGE ( w k s ) O F P I NO VAR V A R M I D D L E AGF C O N S T A 4 2 3 . 9 .. . F i C u r c P . 14. R e g r e s s i o n of. M i d d l e - P o i n t o n A g e : . J L R — C O E F F F R A T I O F P R O B S T D ERR S T C ERR B ( B ) I B ) ( A ) ( B ) - 6 . 2 4 7 2 9 . 7 3 0 . 0 0 0 0 1 3 . 1 2 1 . 1 4 6 I 1 0 " . S T D FPR (Y ) 5 6 . 2 7 THE " . " AND " * • • ARE USED TO P L O T THF R FOR ESS I CN L I N F ; T H E • • * • ' I S US EO W H F N A P L O T P O I N T C O V F R S D A T A AN I S T E C . F R " I " , B E T W E E N I ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 4 » I D A T A P O I N T S " C " RE PR E S E N T S 2 OR FEWER O A T A P O I N T S ; " A " R E P R E S E N T S 3 9 OR MORE D A T A P O I N T S  0 / y = 4 2 3 . 9 - 6 . 2 4 7 x / / / J / / / / _/ / 0 / / 0 / / _ / 0 / / RSO 0 . ^ 5 2 2 P O I N T S 9 1 0 . 0 7 2 0 . 0 i „ 5 3 0 . 0 " 3 4 0 . C 1 5 0 . 0 / / / / / " " / / / / / ~ I I I I I I "I I inn ii iiiiIMI uii i\IM7i11un\ 111II\IiI\I1171111Hi111IIiiI\Ini111mili1 u/1I\I\Ii1i11nil 111IIi / l 5 . 0 0 0 7 7 . 2 0 0 9 9 . 4 0 0 1 1 . 6 0 1 3 . 9 0 1 6 . 1 0 O I S T A N C E BETWEEN S L A S H E S ON THE X - A X I S I S 0 . 1 1 0 0 0 0 0 0 0 0 A 1 (1 1 2 1 2 1 3 6 3 t 5 * 6 " 1 4 0 1 C 1 1 0 1 1 0 0 r r 1 1 1 1 . 1 3° 1 . 1'" 6 ' . 1 " 4 3 . 1 I 2 4 . 1 i T 4. ' °3r 0 6 7 .<•• 9 4 ,° . r 9 2r> .0 91 > . r H<>1 . 1 •f72.r H 5 3 .f . -134 . 0 " 1 5 .0 l». 7 7 7 . 0 _ " 7 5 . .C 7 3 3.C 7 2 c . 0 7 1 1 .0 6 P? 6 6 1 . I _ '" 6 4 4 . 0 " 625 . " 61 6 . 0 5 r i 7 . ( 4 6 . . i 4 4 9 . 0 " 4 : - , . ( • 4 11 .'• ' " . I ' 4 7 3 .( 444 . . ' 4 ? 6 . \" • 4 1 ' . . . ' 3 1 7 . •.• 3 7 f . : 3 4 9 3 4 1 . 1 ' ? l . i ' 3 1 2 . . ' 2 4 . 1 2 4 4 . 1 2 2 6 . '.1 2 " i 7 . i 1 S - 1 . ' 1 6 9 . 0 140. . -l-> CD Cn x = AGE ( w k s ) r F i g u r e F . 1 S . R e g r e s s i o n o f E n d - F t o i n t o n A g e : J L R C O N S T A 3 9 6 . 2 c n t r r B - 5 . 9 0 3 F w A T I O ( R ) 5 1 .46 F I ' R I ' R ( R) r. ocoo s r o I'KR ( A t 9 . 4 ? 4 ST(< FRR I B I I . 82 ?f> STO TRR ( V | 6 9 . 1 5 O E P I NO V A R VAR ENO AC E THE ANO « * • ' A R E USEO TO PLOT T H E R C C R E S S I C N L I N E ! T H F " * " I S USED WHEN A P L O T P O I N T C O V E R S D A T A P O I N T S AN I N T E G E R " l " , B C T W I E N 1 ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 3*1 D A T A P O I N T S _ « C " R E P R E S E N T S 1 OR FFWF.R C A T A P C I N T S ; " A " R E P R E S E N T S 2 9 OR MOP F D A T A P O I N T S 7 4 0 ' . 0 " -/ / y ' 3 9 6 . 2 - 5.903X / / / R7.i 6 2 0 . 0 5 0 0 . 0 Si ft i." 3 8 0 . 0 " 2 6 0 . 0 1 4 0 . 0 7 4 0 . ' 7?i* . ' -716 . • • 7 o 4 . l A •''2 . 0 6 8 2 . i _ 6 * . ' * 6 5*-6 4 4 . 1 6 V . ' I. 2.' ... 6( .  ) l " ' T o / n 1 / 0 1 / 1 1 / _ / _ 0 / "" " "" • " ii\iiiiiiiii\iiiitii\i\tiiiiiiii\iiiii\iii\iiitiiiii\iiiiiiiii\iiiiiiiii\iiiiiiiii\\iiiitiit\iiittiiii\ 5. OOO 7 7 . 2 0 0 9 9 . 4 0 0 11 . 6 0 1 3 . 8 0 16. 01 ST A N C F BETWEEN S L A S H E S ON T I C X - A X I S I S 0 . 1 I C O 5'>6 . 1 C U4 .'• ' • 7 7 . ' 16'. . i 6 4 * . ( 5 3 4 . ' '• ' * 2 4 5 o ' . r 4 7 6 . 1 4 6 4 . . " 4 ' .2 .1 4 4 1 . 0 4 7 * . 1 4 1 6 . ' 414 . 0 3 6 * . ' 3 ' ' 7 . '7 3 ' ' • 5 t 1 * . •; 7 9 6 . : ">4 . 1 272 . 1 2 6 2 . ' 2 4 , * . ' 2 *!• . ' ' 2 24.C 2 1 7 . 0 -» >- 0 1 * * . 0 1 7 6 . i 1 >-4.0 ' 1 5 ? . ' . 1 * i ' I — 1 CD c n x = AGE ( w k s ) Figure F.16. Regression of Mean F on Age: JLR C F P I N O CON S T C O E F F F K A T I O FPROR ^ T l ) ERR S T O FRR S I C ERR R SO VAR V A K A B ( R l ( B ) ( A ) < 0 ) ( Y ) MEAN F AO F 4 1 5 . 1 - 5 . 9 1 0 4 4 . 2 3 0 . 0 0 0 O 1 0 . 1 8 O . e S f l f 7 4 . 6 7 0 . " 7 5 7 T H E " . " A NO ••*•• ARE USE C TO P L O T THE R E G R E S S I O N L I N E ; I M F » * " I S U S E D WHFN A P L C T F C I N T CCVERS D A T A P O I N T S AN I N T E G E R " I " , B E T W E E N I ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 4 * 1 C A T A P O I N T S " 0 " R E P R E S E N T S 2 OR FEWER OA TA P O I N T S ; " A " R E P R E S E N T S 3 9 OR MORE D A T A P C I M S 1 I C C . 115.1 - S.910x 9 2 0 . 0 I K l ' » l " f I 74 J O-J I I 1 o 7<. 95t-o »,i O" 11 II 560T5 -3 8 0 . 0 2 0 0 . 0 / 0 / 0 / / 0 / J _ To I l / / 0 - * / 0 / 0 / 1 / / 0 / 1 _ / T I 11\111/11111\1111nAi\111111111 \ iuiKiii\iiiiiiiii\/iiiut/i\iiuiiiu\iiiunii\i\jiuiiii\iiiiiiiii\ 5 . 0 0 0 7 7 . 2 0 0 9 9 . 4 0 0 1 1 . 6 0 1 3 . 8 0 1 D I S T A N C E BETWEEN S L A S H E S ON THE X - A X I S I S 0 . 1 1 0 0 366 34(i H IO 31? 7<~4 ' 7 76 T 8 7 4 -727 6 V f 14 S O , , •'. 7* ' 16 1 r ' 4 2 624 6 ! 6 8 8 4 7 1 4 34 416 3 0 B >"! ' •<62 3 44 ^2 6 3f 8 ?or. 272 254 21 i-•»o o 6 . o o X = AGE (wks) or- p W R R t- r, i N T Hp » AN | M 1 2 6 0 . 104C. 5 3 2 0 . 0 (3 g " 6 0 0 . 0 " ' I NO V A A C E . " ANO " ' I C E * " I " P P E S E N T S / / / / / / I I I I "" I I I I I I I I I I / / I / / I I Figure F.17. Regression on Beginning-Point on Age: DAE ^ ^ C C N S T ' C O E F F " " F U A T I O F U R O R " S T O E R R " ' S T O ERR S T O F P R " P S 0 ~ A II (IM ( 0 1 ( A l ( B l ( Y I 431.11 - 2 . 3 1 6 C . f 6 5 3 C . 4 2 1 0 3 6 . 3 6 2 . 8 3 0 1 3 8 . 7 0 . 0 0 3 5 ' " A R E C S F O T C P L O T T H E RrGRESSICN L I N E : T F E " * " I S C I S C O W H E N A P L O T P O I N T C C V E R S D A T A P O I N T S . B E T W E E N 1 A N O 1 , R E P R E S E N T S A P P R O X I M A T E L Y 2 * I D A T A P O I N T S 1 O R F E W E R C A T A P C I N T S \ " A " P E P R F S E N T S 2 0 O R V O R F D A T A P O I N T S " " " ' ' ' o " ' y » 131.8 - 2.316x / / / / / / / / . / 0 ii\niniiii\iiiiin\i\iiiiiiiii\iiiiiiiii\iii\iiii\iiiiinii\iiiiiiiu\iXiiuii\iiiiiiiii\iiiiiiiii\ 5 . "Al 7 7 . 2 0 0 9 . 4 0 . 1 L F J 1 1 . 6 0 13 1 3 . 8 0 1 6 . C I S T A N C E B E T W C E N S L A S H E S C N_ T H C _ _ X - A X I S _ l S _ 0 . 1 1 00 _ 1 2 6 0 . 1 2 3 8 . 1 2 1 1 . 1 1 0 4 . 1 1 7 2 . I 1 6 0 . " 1 1 2 « . 1 1 16 . 1 0 3 4 . 1 1 6 2 . 1 04 0 . 101 <>. " <J '15.0 Y74 . 0 0 5 2 . 0 "3 .1 .0 113 . 0 8 8 6 . 0 " 6 4 . 1 842 . 0 K 2 0 . 0 70.8 .0 7 76 . 1 7 4 . 0 7 3? . f 7 1 0 . 0 6 8 8 . 0 6 6 6 . 0 6 4 4 . 0 6 2 2 . 1 6 0 0 . 0 5 7 3 . 0 5 « - 6 . 0 c 3 4 . 0 5 1 2 . 1 4 0,1.1 4( 3 . 1 4 4 6 . 0 4 2 4 . 0 4 0 ? . i 3 8 1 .0 3 5 8 . 0 3 3 6 . 0 3 1 4 . 0 2 9 2 . 1 2 70 . 0 2 4 8 . 0 2 2 6 . 0 2 1 4 . 0 l 3 2 . 0 1 6 0 . 0 0 0 x = AGE (wks) Figure F.18. Regression of Middle-Point on Age: DAE D C " 1 NO VAR V A R MI D O L E AG F THC " . " ANO AN I N T E O E " i " R E P R F " 1 4 0 3 . 1 1 4 C . a I t-j 1 8 8 0 . O „ 6 2 0 . 0 C C N < T C U F f F F K A T I O F P R O n S T O HRP ST C ERR STO ERR R SQ A F) ( B I ( B ) ( A ) ( B ) 1 Y ) 5 6 6 . 2 - 9 . 2 9 8 5 . 5 4 0 0 . 0 1 8 7 5 0 . 5 9 3 . 9 . 1 1 5 3 . 0 0 . 0 2 8 5 I S US ED WHEN A P L O T P O I N T C O V E R S D A T A P O I N T S 3 * 1 D A T A P O I N T S APE USED 'TO P L O T THE R F C P E S S I C N L I N F ; T H F " * " " I " , D E T w C F N 1 AND 9 , R E P R E S E N T S A P P R O X I M A T E L Y F N T S 1 OR F F K F R C A T A P C I N T S ; " A " R E P R E S E N T S 2 9 OR MORE DATA P O I N T S 566.2 - 9 . 2 9 8 X I l\l II1111 111II \ 1111111/IMI 1111111 \ III A111 IMI IIIIII IM IIIIIIII \ll\l II111 \l 1111111 IM 11111111\ 5 . 0 C 0 7 7 . 2 0 0 9 . 4 0 0 10 1 1 . 6 0 1 3 1 3 . 8 0 1 6 , U STANCE B E T W E E N S L A S H E S ON THE X - / 1 X I S I S 0 . 1 1 C 0 I 4 . 1 0 . 1 3 7 4 . 1 34«. 1 3 2 2 . 1 2 1 6 . 1 2 7 " . ' 1 2 4 4 . ' 1 2 1 8 . 1 1 9 2 . 1 1 6 6 . 1 1 ' . ( ' . 1 1 1 ' . 1 1 8 . 1 1 6 2 . 1 0 3 6 . 1 1 1 0 . 9 8 4 . 0 9 " :n . r " 93? .1 ' 91/ ,i> 8 » 0 . 0 8 5 4 . C 8 2 J . 0 8 0 2 . 1 7 It, . 0 74.1.1 7 2 4 . 0 (,•>.•> . 0 6 7 2 . 0 6 4 f . 0 6 20 . 0 4 9 4 . 0 56-3 . 0 5 4 2 . 0 4 1 6 . 0 411. 1 4( 4 . 0 4 3 8 . 0 4 1 2 . 0 3Mh . r 3 6 0 . 0 3 3 4 . 0 " ' 3.") • » . . " ' 2 8 ? . 0 2 4 6 . 1 2 3 0 . O 2 1 4 . 0 1 7 8 . 1 14 2 . 0 * 1 2 6 . 0 1 0 0 . C 0 0 CD CD x = AGE (wks) Figure F.19. Regression of End-Point on Age: DAE ii! t> I M I f.CMsT enrrr F I < A T H : FPP . I 'H sin E R R sn> F U R S T D E R R R S C V A R V A R A Fl I P ) ( R I ( A ) ( R l ( Y ) F N O A G E 4 4 5 . 1 ) - A . 1 3 3 2 . 0 H 5 0 . 1 4 6 3 3 6 . 6 5 2 . 8 6 2 1 3 " . R C . 0 1 C 9 T H R Ann A i ' r tsm m P L O T Tnr pre-- r s s I C N L I N E ; T H E is U S E D H H F N A P L C T P O I N T C C V E R S D A T A P O I N T S A N I N T FGFr< " I " , B E T W E E N 1 A N 0 9 , R E P R E S E N T S A P P R O X I M A T E L Y 2 * 1 D A T A P O I N T S • •< • " R F P 3 F S F N T S 1 OR FFWFR OATA P C I N T S i " A " R E P R E S E N T S ?P_OR MC1R E DA TA_ P O I NT S _ _ _____ " .o - " " ' " " ' * ' ~ ' ' o " / y = 4 4 5 .8 - 4.133x 0 / / / / . 0 / / / 0 / 0 5 C C . C - 0 / _ _ _ / 0 / / 0 / / g ^ _ „ / . 1 o 6 2 ^ . 0 - 1 6 2 0 . o / 0 0 6 1 2 . 0 g / o ' " • " / 1 0 B 3 0 . r o / o o / o / o / l =_ a e '/ 3 0 2 _ / 0 1 1 I 4 4 0 . 0 " " - " " " 1 ' " "1 >. I • • 1 I 1 / 0 I 1 / 1 1 2 / 0 1 1 0 _ " / ""_' "6 1 / 1 1 1 / 0 3 P / 1 3 0 1 2 6 C . C - 0 0 • 1 / 0 1 / 0 0 / / 0 0 / / / _ _ _ _ _ _ / - - - - — - - -/ / i II in 11 II i n II II I\I i II ilium 11111 II 11 \ i u Su II IMI 111 II mn II u 11 i\u\iii II i \i II 111 II IMI 11111 m 1 . 1 ( 3 7 7 . 2 f 0 9 . 4 0 0 10 1 1 . 6 0 13 1 3 . B O 1 6 . 1 1 . C I STANCE . H F T W F F N S L A SHE _S _CNI.THE X - A X I S J S C . 1 1 C 0 _ _ _ _ _ _ x = AGE (wks) O ' l f . 0 9 4 2 . 1 9 4 . 0 " 2 6 . 0 " O H . 1 P " 0 . 0 0 • ( 7 2 . 1 8 4 4 .1." 8 3 6 . 0 8 I Q , 0 8 0 0 . 1 7 f> 2 . 0 7< 4 . 1 74 (. . 0 7 2 8 . 1 7 10 . 1 6 9? . 0 6 7 4 . 1 ' 6 4 6 . 1 6 ? R . 0 6 ? 1 . 1 1 2 . 0 4 84 . 1 4 6 6 . 1 4 4 8 . 0 4 3 0 . 0 4 1 ? . n 1 4 U 4 . 0 0 4 76 . 0 4 4 i j . 1 4 4 0 . I " 2 4 2 2 . 1 3 . 4 0 4 . 1 • 3 8 ' . . 0 V r l . " 4 3 5 1 . 0 7" ' 3 32 .C 4 3 1 4 . 1 3 2 n 6 . 0 1 2 7 8 . 1 1 2 6 O . o 2 4 2 . 0 2 2 4 . 0 2 0 6 . 0 1 0 3 . 0 1 7 0 . 0 1 5 2 . 1 l 3 4 . 0 ' l 1 6 . 1 0 9 8 . 0 0 R O . 00 C K 1 VAR I K A N I " 1 2 2 C . ' 1 0 2 0 . 8 2 0 . 0 n o A G E " . " ANO " N i t OCR " 1 " R E P R E S E N T S / / / / / / " / / / / . _ ' / / / I / / " / / / / / 7 / / / / / Figure F.20. Regression of Mean F on Age O n t l S T " " ' C O E F F E R A M O FI 'Rl ' .H A n (i' i (R i 5 0 1 . 7 - 6 . 1 6 9 3 . 9 4 0 0 . 0 4 5 9 • " A F T U 5 " 0 TO PLOT TNT R FOR C SS I ON I I N F ; THF ' • « • ' . B E T W E E N 1 A N O 9 , KE PR bS FN T S AF F P C X I M A T FL V 3 * 1 DAE ? T 0 E K R S T C E R R I A I I It I 3 9 . R O 3 . i c e I S U S 5 0 W H E N A P L C T F C I N T C A T A P O I N T S S T C E R R R S O ( V I 1 ? 1 . R C . 0 2 0 4 C C V F R S D A T A P O I N T S 6 2 0 . 0 4 2 0 . 0 2 2 0 . 0 1 0 _ R _ _ F E W E R _ C A T A P O I N T S ; " A " R E P R E S E N T S y a 501.7 - 6.169.x 2 9 O R M O R E D A T A P O I N T S / / I IIII u III I ii mi i\i\ 11111 u 111 min in\ im\ii n\ in 111 ii 111 III mi 11 IIII n 11 in III i \ tin nun 1 2 2 " . I 2 0 0 . 1 1 I " . 1 1 * 0 . I 1 4 0 . I I 2 0 . 1 1 1 0 . 1 0 * o . 1 0 6 0 . 1 0 4 0 . K 2 0 . 1 0 0 0 . «po. o 940.n 9 4 0 .C 9 2 0 . o ooi.n 8 8 0 . 0 R 6 0 . 0 8 4 0 . 0 8 2 1 . 0 HOO. o 7 1 0 . 0 7 6 0 . 1 7 4 0 . 0 7 2 0 . 0 7 0 0 . 0 6 " C ' . 0 6 6 1 . 1 6 4 0 . 0 ' 6 ? 0 . 0 6 0 0 . 0 1 8 0 . 0 1 4 1 . 0 5 4 0 . 1 1 2 3 . 1 I f C . O 4 H G . 1 4 6 0 . 0 4 4 0 . 0 4 2 C . 1 4 X . 0 " 3 S i . 1 3 6 0 . 1 3 4 1 , 1 3 2 0 . 0 3 0 0 . 0 2 P O . 0 2 6 0 . C 2 4 0 . 0 2 2 0 . 0 5 . 0 0 0 0 1 S T A N C E 7 7, BETWEEN S L A S H E S 2f 0 CN THE X - A X I S I S 9 . 4 0 0 10 0 . 1 1 0 0 1 1 . 6 0 13 1 3 . 8 0 1 6 . 0 0 X = AGE (wks) 1)1' l> 3EC I N T(-' AN t . ~ (I 1 2 4 3 . 1 1 2C. l no V A 3 AOC - >i .ii A ' l . "< I M E O T k " I " , OEPK.H S CNT S / / / / I I I I I I I I I I I I I I I I I I I I I I / 5 6 0 . C I*C •figure F . 2 1 . Regression of Beginnin_-Point on Age: MJK _ __ r.rNST C O F F F T P A I I C F P R O P S T O „ K R S T O E R R S T D E R R R S Q " A p. ( H I ( 0 1 ( A ) ( R » ( Y ) 3 6 6 . 6 - 2 . ' , ' . ' ) 2 . 2 0 R 0 . 1 3 4 4 2 3 . 2 6 1 . 7 E C I C R . 5 0 . 1 0 9 P •• A P E L S E O Tl) P L O T THF R E C E S S I O N L I N E ; T H F " * " I S OS F D WHEN A P L O T P O I N T C O V E R S O A T A P O I N T S B E T W l l U 1 A N D 0 , F F P U E SCr) T S A P P P O X I MA TF LY 3 * 1 D A T A P O I N T S 1 O R F E U E R C A T A P C I M S ! " A " R F P P F S E N T S 2 9 OR MOR F OATA P O I N T S _ o " " ' y = 3 6 6 . 6 - 2 . 6 U 5 x 0 0 0 2 " \ " 1 0 i I\I III 1111 I\II 11 III i I\II 111X1 I\IIIIIIIII\I 11 \ 111 I\II IIII i II\II An 11 i\i\i u u i\m inn iMiu in n\ 5 . 3 1 1 7 . 2 0 0 6 9 . 4 0 1 1 0 1 1 . 6 0 . 1 3 1 3 . R O 1 6 , D I S T A N T Ri!TV,CrN SLASHES C I * THE X - / X I S IS O . l l ' O 1 2 4 0 . 1 2 1 8 . 1 1 9 6 . 1 1 7 4 . 1 1 5 2 . 1 1 3 0 . 1 l v » . 1 0 8 4 . 1 0 6 4 . 1 0 4 ? . l i ? 0 . 9 9 8 . 0 9 7 6 . 0 ° 5 4 . 0 9 3 2 . 0 9 . 0 Hi? .3 . 0 H 6 6 . C 8 4 ' . . 0 8 2 2 . 0 P O O . 0 7 7 3 . 0 7 5 4 . 0 7 3 4 . r 7 1 2 . ( 6 9 C . 0 6 6 8 . 0 6 4 6 . 0 6 2 4 . 0 6 0 2 . 0 4 8 1 . C 5 5 8 . 0 5 3 4 . 0 4 \ 4 . 0 4 9 ? . 0 4 7 0 . 0 4 4 0 . 0 4 2 6 . 0 4 1 4 . 0 3 8 2 . 0 3 6 0 . 1 3 3 8 . 0 3 1 6 . 0 2 9 4 . 0 2 7 2 . 0 2 5 3 . 0 223. r ? 0 ! > . 0 1 B 4 . 0 1 6 2 . C 1 4 0 . 0 0 0 r o o r o x = AGE (wks) Figure F.22. Regression of Middle-Point'.orrAge: MJK . _ . C f l F F F F I - A T I C FPROP STO ERH STO EP.R STO EHR RSO R ( B l ( B l I A I ( B l ( V | - C . S 3 3 3 0 . 2 3 0 4 0 . 6 3 6 1 2 5 . 4 1 1 . 9 4 4 1 1 8 . 5 0 . 0 0 0 9 TO P L O T THE R E G R F S S I C N L I N E : T h E " * " I S U S E D WHEN A P L O T P O I N T C O V E R S D A T A P O I N T S AN I N T E G E R " I " . B E T W E E N 1 ANO 9 , R C P P C S C N T S A P P R O X I M A T E L Y 3 * 1 OA TA P O I N T S 0 ~ P VAR MI 0 0 I E T E r I N I ) C C N S T V J 1 A AO, E 3 8 5 . 1 ' . " AND ' • * • • \ R F US C .D 1 1 7 0 . R F p a f S E ' l T S / / / / / / / / / 9 5 C . C i 5 1 C . C 2 S C . C 7 0 . 0 0 1 OR FEWER C A T A P C 1 N T S : y = 385.1 - 0 . S 3 3 3 X • A " R E P R E S E N T S 2 9 OR MORE D A T A P O I N T S / " / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / i I\I 11111111 \ u 11 ii 111 \ ii 11 I\I 11 \ 111 u 111 n 111 i\u 11 \ ii 111111 I\I i\i 1111 1111 I\I i III i ii I\I 11111111\ 5 . O C O 7 . 2 0 0 8 9 . 4 0 O 10 1 1 . 6 0 . i 3 1 3 . 8 0 1 6 . r i S T A N C E BETWEEN S L A S H E S VM THF X - A X I S I S r . 1 1 C E, 1 1 7 0 . 1 1 4 ? . 1 1 2 6 . 1 1 0 4 . 1 0 8 2 . 1 0 6 1 . I 0 3 8 . 1 0 1 6 . " 9 4 . 0 9 7 2 . 0 9 5 1 . 0 " 2 3 . 0 1 0 6 .0 884 . 0 « 6 2 . 0 8 4 1 . 0 111 8 . 0 7 9 6 . 0 " 774 . 0 7 5 2 . 0 730 .1 7 0 8 . ( 6 8 6 . 0 6 6 4 . 0 6 4 ? .0, 6 2 0 . 0 613 . 0 6 76 . 0 1 5 4 . 0 5 32 . 0 ""51 i . i " 4 8 H . 0 4 6 6 . 0 444 . 0 4 2 2 . 9 4 0 0 . 1 " 3 7 •> . 0 " 3 5 6 . 0 3 34 . 0 3 1 2 . 9 2 " 0 . 0 268 .0 ' 2 4 6 . 0 " 2 2 4 . 0 2 O 2 . 0 1 8 0 . 1 1 5 8 . 0 1 3 6 . 0 1 1 4 . 0 9 2 . OC 7 0 . 0 0 00 oo O CO x = AGE (wks) rJ I / . » . < J 1 . < 2 ; ; -C -t r~ < «— CM G < J ~ - f \ . - J ' - C P - . — O 9 - <- c • • a o — —• o — — : — c o O U_ • X < - O l - > i —' C <r. ~ r- —• c ^ 1 / 1 i a. U; '_• u ' I a < »— r- < , u r". c a;' U-i — z • < oj Q C '.C C_> . "S. V . I «s. V . "N. -S. >s. * C — rj • j - i f\j • . \ ->v \ "v. I ^ -^ C- ' •«v • < — I T • -. N. x . t ^ _ . * a f i r p C f A N f THE I NI) A f . f " . " ANO C O A T A 3 7 4 . 0 " « • • AKb . s e c F i l j w r e . F . 2 4 . R e g r e s s i o n o f Mean F_ o n A g e : C O E F F ' - F P ' A T 10 F P m m 8 ( H ) ( H ) - 2 . 0 3 . 1 - 6 1 2 C . 2 0 2 4 T C P L 0 1 T H E R C G R E S S I C K L I N E ; T H E " *•• Af; I N T EG E" " I " , B E T W E E N 1 AND <), K F P R F S E N T S A P P R O X I M A T E L Y n o « O F P P F S E M S 1 OR F FWFR _C AT A P O I N T S J , R E P R J S F N T S _ 9 H C . 0 " - " " ~" " ' " ~ / y = 3 7 " * . 0 - 2.038X / / / / / / / C jfto ERR I A l 2 C . S 7 I " U S E D WHEN 3 * 1 D A T A P C I N T S 2 9 OR MORE D A T A P O I N T ? MJK S T D CPR S T D CPR ( H I ( V I 1 . 6 C 5 9 7 . 8 . 6 A P L C T P C I N T C C V F R S O A T A R S C G . 0 0 6 6 P O I N T S R 3 0 . C _. 4 8 0 . 0 i ^ 5 3 1 . i C ~ 3 8 C . O 0 1 0 | 1 1 i 1 * n 0 1 1 r ' ' " 1 2 0 i 0 1 0 2 3 l 0 0 0 0 2 0 0 l 1 1 1 2 - 0 . 0 " ?eo. o 9 6 4 . 0 9 4 1 . 0 9 3 4 . 0 9 2 0 . 0 9 0 5 . 0 •<50 . 0 8 7 5 . 0 8 6 0 . 0 8 4 5 . 0 P 3 0 . 0 8 1 5 . 0 8 0 0 . 0 7 3 5 . C 7 7 0 . 0 7 - > 4 . C 74 0 . 0 7 2 5 . C ' 7 1 0 . 0 5 9 4 . 1 0 6 P 0 . O 6 6 5 . 0 6 4 0 . r 0 n s . r 6 2 0 . 0 6 1 4 . 0 4 9 C . 0 5 7 5 . 0 5 6 1 . 0 44 4 . " 430 . 0 5 1 4 . 0 4 : 1 . 0 4 8 5 . r 4 7 0 . 0 1 4 4 4 . 0 0 4 4 0 . 0 4 2 5 . r 1 4 1 0 . 0 0 V )4 . 1 3 3 8 0.1 3 -<64. p " 7 " 3 5 1 . 1 • 3 3 5 . 0 4 3 2 0 . 0 4 3 0 4 . 0 2 2 7 0 . 0 2 2 7 5 . 0 1 2 6 3 . 0 1 2 4 5 . 0 1 2 3 1 . 0 5 . 3 < 0 0 1 STANCE P E T W F E N S L A S H E S , 2 u 1 8 O N T H F X - A X I S I S 0 . 4 C 0 10 0 . 1 K C 1 1 . 6 0 13 1 3 . 8 0 1 6 . 0 1 x = AGE (wks) APPENDIX G LINEAR REGRESSIONS OF V/TTHIN-UTTERANCE RANGE ON AGE y = a + bx y = Fundamental frequency (Hz), x = Age (wks) The following figures represent xerox reductions of computer print-out. At the top of each figure are listed the constant a, the coefficient b, and the F-probability. The "." and are used to plot the regression lines, "*" being used when a plot point covers data points. Integers (I) represent approximately 2 x 1 data points; 0 represents 1 or no data points; A represents 20 or more data points. If 'D-01' follows any number in the printout, that number must be divided by ten. Figure G.l: CAB Figure G.2: AMG Figure G.3: AMR Figure G. M-: JLR Figure G.5: DAE Figure G.6: MJK O E P i \o V A « V A R R A N G E A G F T H E " . " ANO RSQ _ _ ^ B " o e G.l. R e g r e s s i o n o f j v i r h i n - U t t e r a n c e R a n g e o n A g e : CAB T f l N S T ~ ~ " C O F F F " " F H A l l ' C FPRnS" ' " ' S T 0 ' ~ F ~ R R * ~ S T C ERR* S T O ' F . R R A B ( B > ( B ) ( A l ( B l ( Y l - 7 . C 6 5 A . A i l 3 2 . 6 5 0 . 0 0 0 0 1 8 . 0 5 1 . 1 71 E C . O S 0 . 1 4 4 1 " ARE L S F O TO P L O T THE R E G R E S S I O N L I N E : THE " » " I S U S E D WHEN A P L C T P C I N T C O V E R S D A T A P O I N T S <" 5 7 C . O / ' y = - 7 . 0 6 5 + 6 . 6 9 1 X / / / 1 5 7 0 . 0 5 5 8 . 0 5 4 6 . f 5 3 4 . 0 5 2 2 . 0 M P . O i / 4 C K . 0 1 / 4 8 6 . 0 / 1 4 7 4 . o / 4 6 2 . 0 4 5 C . 0 / I 4 5 0 . 0 4 3 3 . 0 / 4 2 6 . 0 / 4 1 4 . 0 / 4 0 2 . 0 / 1 3 o n . 0 / 2 3 7 8 . 0 / 3 6 6 . 0 / 354 . 0 / 7 42 - 1 3 3 C . 0 / 3 1 8 . 0 / 3 0 6 . 0 B / 2 9 4 . 0 / 2 a 2 . 0 a / 1 2 7 0 . c 9 / 1 2 1 8 . 0 / 1 2 4 6 . 0 / 2 3 4 . 0 r i / 1 1 2 2 2 . 0 £ 2 1 1 . i i / 1 1 21 7.0 193 .0 a. / 1 / 1 1 1 1 1 2 1 8 6 . 0 1 7 4 . 0 " / 1 2 1 2 1 62 / 2 1 1 1 5 0 . 0 / 2 1 1 1 * 1 3 0 . C / 4 1 2 126.0 / 1 3 1 4 3 1 1 4 . 0 / 1 1 1 1 • 2 10 2.0 9 0 . CO 2 2 1 . 3 4 ° 0 . 0 0 / 2 2 3 2 2 1 7 7 8 . 0 0 i / 1 1 1 4 • 2 1 6 h . 0 0 / 2 8 1 a 2 1 6 4 . 0 " / 1 . 4 3 3 1 1 ? 4 2 . 0 0 / . 1 2 4 2 1 4 1 3 0 . o n / 4 5 2 1 3 1 8 . 0 0 / 1 . 4 6 1 3 1 1 1 1 6 . 0 0 0 1 - 6 . 1 0 0 1 - 1 8 . 0 0 -30. 0 0 I I 1 - 3 0 . 0 0 ro o 5 . 1 " i 7- 8 8 . 4 f 0 10 C I S T A N C ? BETWEEN S L A S H E S ON THE X - A X I S I S 1 1 . 8 0 14 C.170C " " "x'VAGE ~(wks> 1 5 . 2 0 1 6 1 8 1 8 . 6 0 20 2 2 . 0 0 _____ _ Z.6ur>e <».Z. K'gression of Within-Utterance Range on Age: AM3  I NO " " " C O N S T ' ~ CO E F F F P A T I O ~ ~ ' " F PR OR STO FRP ~ S T l f t "PP ST C FRR RSO VAR A D ( B I ( P I ( A l ( P I ( V I AGE 4 6 . 7 2 3 . 2 4 8 1 1 . 7 * C . 0 U 0 9 1 1 . O H O . Q 4 7 1 5 7 . 5 2 " i . i - f l . . « A N O » • • • ARE U S E C T O PLOT THE R E G R E S S I O N L I N F ; THF " * ' • I S USED WHEN A P L C T P C I N T C C V F R S OATA P C I N T S 3 1 " y a U8.72 + 3.248x ' 1 J'^ ' / ' ? s ) / 2 3 2 / 2 7c / "/••« / 2<-l / 1 ? ' - 4 / 1 2<- ' / ' "3-1 / 7. '??!• 1 1 2 1 9 / 2 1 2 / 1 2 . 4 / 1 ' I - • ' / 1 3 / _ ^ ~ ] , / 1 1 1 7 7 - I 1 171-/ 3 1 4 1 ( 0 / 1 2 3 1 5 . / _ 1 1 '•••> I ~ i 3 " " 1 " l'? / 1 4 2 1 3 ' . / I 1 1 2 1 2 3 / 1 1 1 2 1 2 1 / 1 2 2 1 1 4 / _ _ l 1 i L l 7 ' - " " ~ 5 2 7 .' "V •• I 5 3 1 4 / 5 . 2 4 » / . . / 5 2 3 1 7 0 . / 2 5 . 1 2 1 7 2 . / * 4 1 1 2 _ ' - 4 . / r ""~ ~5 - ' 2 r " 4 6 . / I 5 1 2 3 5 4 ) . / 1 4 1 1 1 4 i . / 3 4 1 1 2 3 7 . 1' 2 1 3 i . / 1 3 2 2 ^ ^ I ? 3 . " / I * 3 ••"" " " " 3 ' " ~ " " " 2 " U - . / 1 4 1 3 1 3 3 . ' ' / 2 3 1 2 . 0 / - 4 . i / - 1 2 . / - 1 9 . " / " " ~ "" / - ? 3 . ti\u 1111tu\iiit 111\i \11nuut\uuI\I11 \ 111in111 \n 11 unt\iiX11ui \uu1111I\Itut/ni\ttuutu\ 5 . 0 0 1 7 7 . 2 0 0 9 9 . 4 0 0 1 1 . M 1 3 . 8 0 I S I L " ' D I S T A N C E BETWEEN S L A S H E S ON TEC X - A X I S I S O . 1 1 0 0 x = AGE (wks) Figure G.3. Regression of Wilhtii-lTtleruruje Range on Age: AMR I K A T I U ri'Knn sin i n< sin FPR S T C C F P I NO CONST C D E F F ( R O F I ' R O H i l l ) I H i S i l l    S T FI-'R • ' S C VAP VAR A P ( 8 I i n ) ( A l ((I I ( Y I R A N G E AGE 3 4 . 7 1 3 . 5 4 6 8 . 7 0 6 C . " 0 3 5 1 6 . 3 9 1 . 2 0 2 5 5 . 9 0 0 . ' ; 2 4 3 THE " . " A NO ARF U S F C TO P L O T T H E R F C P E S S I O N L I N E ; THF • ' « • • I S USFO WHEN A P L C T F O N T C C V F R S OATA P O I N T S AN I N T E G E R " I ' S U E T W E F N 1 A AO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 2 * 1 C A T A P O I N T S » 0 _ _ E P _ I S F N T S l OR FEWER OATA P O I N T S ; " A " R E P R E S E N T S 2 0 OR MORE O A T A P O I N T S  2 9 C . 0 - " ' y o 3 4 . 7 1 • 3 . 5 4 6 X / / / / /" / / / 0 2 3 0 . 0 / / 0 / / „ / g / _____ : £ / ~ 0 U 1 7 0 . 0 - 0 I '•" "** / o o / l / / 0 / / l I / o n o . o - o o / l / 0 / o o / l / 3_ / " 0 / 2 / • l / l 5 0 . 0 0 - 0 2 /~"i5 ~~~ V in 2 / o / o i / / _ n o 7 ~ "" ~r / 0 0 0 0 l l 0 l 0 l l 0 _o_ 0 l l 0 l I 0 2 0 r~ r ?</.'• 7 :\: ? 7 K n 2 7 ? l ? f ( ?••«. 2 A n •><•? ?3 t 2 3 ' l 224 ..... ' 3 1 >: f 21 2 I 2 C I ? ( ' l 194 l 1 •' a l 1 ° 2 2 l rt r, 11' 3 1 6 4 I 1 '-P .. ' 1 ' 2 t 1 4... 1 1 4 ."• c 1 >4 1 ? 3 ] 1 22 f- 1 l r 7 " l 1 • I V --1 3 . °? . * - 1 6 . - 1 . ' 7 4 . 6 4 . «. •> 3 f. •'. 4 4 4 . I S . 4 3 2 . 5 2 6 . •> 2 " . 3 1 4 . *? • * 1 "* - 1 0 . 0 0 . | , - K IIMIIIIIIIIMIiv ii 11 IMI ii 11 ii I\II ii inn iiiriiiui i/in nv i ni i in in i \tt nun I\I in mi i\ II 11 II i in 8 . C O O 9 9 . 4 0 0 1 0 . 8 0 1 2 1 2 . 2 0 1 3 . 6 ' - 1 4 . r - i 0 1 STANCE eETWFEN S L A S H E S ON THE X - A X I S I S O . ? O Q 0 F - 1 1 x = AGE (wks) O E P 1 NO C O N S T CO EE F VAR VAP A B RANGE AGF 9 4 . 5 3 - 0 . 8 3 5 9 THE AND ARE L S E D TO PLOT THE R E G R E S S I O N L I N E AN I N T E G E R " l " , B E T W F E N 1 ANO 9 , R E P R E S E N T S A P P R O X I M A T E L Y " 0 " R E P R E S E N T S 4 OR FEWER D A T A P C I N T S i " A " R E P R E S E N T S _Figure G.M. Regression of Within-Utterance Range on Age: JLR_ F P A T I O ' F P R ' I B STD F K l f S T O C^P ' sfo~'rRR' " RS'J ( B l ( B I ( A l I B I ( Y ) 0 . 4 4 8 3 C . 5 1 C B 1 4 . 3 ? 1 . 2 5 0 1 C 5 . 0 0 . 0 0 0 8 T H E " * " I S USED WHEN A P L C T P C I N T C C V E R S D A T A P O I N T S 8 * 1 OATA P O I N T S 7 7 O R - M O R F OATA P O I N T S ' 1560. \ y = 94.53 - 0.8369X 0 l ' h o . 1 •> ? 8 . 1 4 9 6 . 1 46 4 . 1 '. \ ? . 1 4 ' " . 1 1 36 3 . 1 1 ">36. ', 1 V 4 . 1 ? 7 ? . 1240. . ; 1 ? 4 " . 1 ?. P. 1 1 7 6 . 1 1 4 4 . 1 1 1 ? . 1 H i . 1 0 4 8 . s i K ! » . ft ')84 .-' 9 6 ? . 0 « 920.0 ° ? A . ( .3*3.0 8 k 6 ..• 1 H ? 4 . 0 I 1 0 /•>? .( 7*- r . (• 7? 3. 0 6 9 6 .1 6 6 4 6 ? ? . r I I 600.(5 6 < v ' .0 0 0 0 0 t * . .-s: 4 . 1 4 73.0 \ 0 0 0 4 - , ' M . O 3 7 6 . 0 1 0 3 4 4 . 0 0 (• '< 1 ? . 1 280.0 0 0 ?80.C 1 0 0 0 7 4 * . O / 0 0 ' o • • 0 ~ ' C " ' ? l t . . ' / 0 1 0 0 1 1 8 4 . 0 / 0 1 1 l 1 1 5 ? . 0 / o 2 1 l ? ! ? ' . ' ' / * / 1 3 6 3 4 • '18. C-3 I " / 1 3 8 6 " l " ?4. .- ( " / 0 1 ? I 1 - n . " 0 0 - 4 0 . 0 0 inn i/ititi\ii IIIII\II\II 111/iin irii/\ii/\ II iiiiiinii/i/iiinii it IIII I\IIII iiiin/\ti/iin i\n mum 5 . CCO 7 7.200 9 9 .400 1 1 .60 1 3 . 8 0 16. D I S T A N C E BETWEEN S L A S H E S ON THE X - A X I S I S O . U C O ro I—1 O x = AGE (wks) Figure G.5.Regression of Within-Utterance Range on Age:__DAE P ANO E AG L 1 9 6 . 9 - 6 . 0 2 8 4 . 5 4 5 C . 0 2 5 9 3 4 . 72 2 . 7 11 1 3 2 . 4 0 . 0 2 5 5 ThF » . ' • AND • •« ' • ARE L S E C TO PLOT T H P R E G R E S S I O N L I N F ; T H F • • * • • I S USCO WHEN A P L C T P C I N T C C V F R S O A T A P O I N T S A ' i I N T E G E R " I " , B E T W E E N 1 AND 9 , R E P R E S E N T S A P P R O X I MA TF L V 2 + 1 O A T A P O I N T S »C R F P P F S F N T S _ 1 OR FF WER O A T A P C 1 N T S ; " A " R F P R f S F N T S 2 0 O R _ M O R F _DATA P O I N J S 7 6 0 . 0 - " " ' " ' 0 ~ ~ ' " 7 6 " . 0 / y •> 1 9 6 . 9 - 6 . 0 2 8 x 7 4 4 . i / 7 2 8 . 1 / 0 7 l ? . o / 0 6 9 6 . 0 _ / . 6 < = 0 . 0 " / ' 6 6 4 . 0 / 0 6 4 R . 0 / 6 3 2 . 0 / . 6 1 6 . 0 6 C 0 . O - . 6 0 0 . " / ' * 4 ° 4 . 0 """ / " " * " " ~ " " " 5 6 » . r i / 5 4 2 . 0 / 0 5 " > 6 . 1 / 4 ? , ; . . ( , / 0 4 0<. . 0 / 4 P S . 1 " " " ' / ' 4 7 2 . 0 / 4 5 6 . 0 4 4 0 . C - 0 4 4 0 . 0 / o o 4 2 4 . r / 4 0 8 . 0 / 0 3 " V . O / ' _ 0 " - - • - -\Th.c I - 6 1 . 0 / 0 3 4 4 . 0 / 3 2 8 . 0 / 0 3 1 2 . " / 0 _ _ _ 1 _ _ _ _ _ ! _ _ 2 9 4 . 0 / 1 0 2 6 4 . " / 1 2 4 8 . 0 / 0 0 0 2 3 2 . 0 / 1 0 0 2 1 6 . 1 / 1 . 2 0 0 . 0 / " " ' " " ' ""' " ' - . - . - - - "O* 1 8 4 . 1 / . 0 1 1 6 3 . 0 / . 0 0 . 1 1 5 2 . 0 / 1 0 0 2 1 1 6 . 0 1 2 0 . 0 - 1 2 . 1 2 1 2 - i . r / ' 1 _ _ 1 * _ 1 0 4 . 0 " ' / " " ~ ' " " " " " 2 " ~ \ " ~ " " ~ " T ' ~ 3 " rtp . 0 " / 0 2 2 ? 1?.00 I 1 I 2 4 4 6 . 1 1 / 1 0 2 6 4 0 . 1 1 / 1 5 l . 1 6 2 4 . 0 0 _ / 1 0 _ 0 _ 0 4 _ 8 . 0 0 0 / " " ~ " " " ' " - . , 0 " t l / - 2 4 . 0 1 4 0 . 3 0 • . . - 4 0 . 0 0 ii\nunn/\iiuni\i\/iiiiuii\iniuni\iii\iiii\unnin\iiiiiiiii\i\iiiiin\iiiijiiii\iiiiiiiii\ 5 . 1 ( 1 7 7 . 2 0 0 9 . 4 0 1 10 1 1 . 6 0 13 1 3 . 8 0 1 6 . 0 0 __ _E I < ;I 4 N ( : , : P F T W E E N S L A S H E S ON THE X - A X I S I S 0 . 1 1 C 0 x = AGE (wks) F S C o | 4 3 0 . 0 l 1 3 3 . 0 - 2 0 . CO Figure G.6. Regression of wirliin-Ut terance Range on Aget flJK CEP I V ) C O N S T " O l E F E l - ' H A I I f l F P I . O B STO CEP STC f R P " " ' S T C ERR VAR VAR A e I B ) ( H I ( A ) ( B 1 (Y> RANGE ACE 5 8 . 5 9 „ 3 . 4 7 6 5 . 6 7 9 0 . 0 1 7 6 1 8 . 8 7 1 . 4 4 4 8 8 . C 3 0 . 0 2 2 6 THE " . " A N ) • • » " APE O S E C TO P L O T THE R E G R E S S I O N L I N E ; THE " * " i S U S F O WHEN A P L C T P C I N T C C V E R S O A T A P O I N T S A ' : I N T E G E R " I " . B E T W E E N 1 A NO 9 , R E P R E S E N T S A P P R O X I M A T E L Y 2 » I C A T A P O I N T S " 0 - R E P R E S E N T S 1 OR FEWER OATA P O I N T S : " A " R E P P F S E N T S 20_ OP MORE D A T A PC I M S ~ 7 S C . C ' -/ y = 5 8 . 9 9 + 3.426X / / / / / / / / S t i O . O / " I I I I ^ I 5 " / / / / / / / / / / / / / / 0 / j o ' / ' " / / / - 0 / o _ / 3 / 1 / * / 7 / 1 / 3 / 3 / 1 1 1 2 1 0 0 1 ? i " . . . ^ 2 1 4 l l 1 1 3 7 I 1 2 l 0 C 7 0 ii\iinii/n\iiiitiiii\niii\in\iiiiiiiii\iii\iiii\niiiiiii\i/i\niii\/i\iiiiiii\iiiiiiiii\iiiiiiiii\ 5 . C O O '. 7 . 2 ' n 8 " . 4 ( 0 1.0 1 1 . 6 0 1 3 1 3 . 8 0 1 6 , O I S T A N C F B E T W E E N S L A S H E S CN THE X - A X I S I S 0 . 1 1 0 0 7 ? o . o 7 1 5 . 0 7 0 0 . 0 6 8 1 . 0 6 7 0 . 0 6 5 1 . 0 ~ 6 4 0 . 0 " 6 7 1 . 0 6 1 0 . 0 5 9 1 . o 1 '< 0 . 0 5 6 5 . 0 ' 5 4 C . 0 " 5 3 1 . 0 1 2 " . 0 5 0 1 . o 4 " 0 . 0 4 7 1 . 0 4 6 0 . 0 4 4 5 . 0 4 30 .0 4 l 4 . 0 4 0 0 . r 331.C 3 7 0 . 0 3 1 1 . 0 3 4 0 . 0 3 7 5 . 0 3 1 0 . 0 7 9 5 . 0 ?«r.r " 7 6 5 . 0 7 5 0 . 0 7 3 5 . 0 7 7 0 . 0 ? o i . C 1 9 C . 0 " 1 7 1 . 0 1 6 9 . 0 . 1 4 5 . 0 1 3 0 . 0 1 1 4 . 0 l O O . p " 8 5 . C O 7 0 . 0 0 5 1 . 0 0 4 0 . 0 0 7 5 . 0 0 1 0 . 0 0 - 5 . 0 0 0 - 2 0 . 0 0 07 ro H ro x = AGE (wks) APPENDIX H LINEAR REGRESSIONS OF WITHIN-UTTERANCE RANGE ON DURATION FOR UTTERANCES WITH ONE AND TWO MIDDLE-POUITS y = a + bx y = Fundamental frequency (Hz), x = Duration (csec) The following figures represent xerox reductions of computer print-out. At the top of each figure are listed the constant a, the coefficient b, and the F-probability. The "." and are used to plot the regression lines, """ being used when a plot point covers data points. Integers (I) represent approximately 2x1 data points; 0 represents 1 or no data points; A represents 20 or more data points. If 'D-01' follows any number in the printout, that number must be divided by ten. For each child, regressions of within-utterance range on duration are calculated separately for utterances with one and two middle-points Figures H.l - H.H: One middle-point Figures H.7 - H.12: Two middle-points 213 . F i g u r e H . l . R e p c c G G i o n . o f W i t h i n - U t t e r u n c e Range o n D u r a t i o n — U t t e r a n c e , i d t l i o n e M i d d i e - P o i n t : CAB I N n r.CNST C D t F t - ' • F R A ' T I O F P R n f l STD F R P " S T D E R R ~ S I C F R R RSQ V A R A U ( B ) ( B ) ( A ) ( B I ( Y ) CUR 6 0 . ( 1 0 0 . 6 4 C R 1 7 . 7 0 0 . O 0 0 1 8 . 9 2 3 0 . 1 5 2 3 8 2 . 4 1 0 . 0 8 7 3 . " A NO APE I I S E C TO PLOT T H E R E G R E S S I O N L I N E ; THE " » " I S U S E D W H E N A P L O T P O I N T C O V E R S D A T A P O I N T S 1 5 7 0 . 0 / 5 5 8 . 0 / y = 6 0 . 0 0 + 0 . 6 4 0 8 X 5 4 6 . 0 / 5 3 4 . 0 / 5 2 2 . 0 _ / . 5 1 0 . 0 / . . . A g f ( _ p / 4 8 6 . 0 / 1 4 7 4 . 0 / 4 6 2 . 0 4 5 0 . 0 _ / 1 ; 4 3 8 . 0 ' 4 2 6 . 0 / 4 1 4 . C / 4 0 2 . 0 / 1 3 9 0 . 0 / 1 1 3 7 8 . 0 / 3 6 6 . 0 / ' " 3 5 4 . 0 ' / 3 4 2 . 0 1 3 3 0 . 0 / 3 1 8 . 0 / 3 0 4 . 0 / 2 9 4 . 0 / ~ " " " " 2 8 2 . 0 / 1 2 7 0 . 0 / 2 5 8 . 0 / 1 2 4 6 . 0 / . 2 3 4 . 0 _ / 2 2 2 . 0 I ~ " ~ ~ ' " " ~ " " " " " " " " 2 1 0 . 0 / . 1 1 9 8 . 0 / 1 1 . 1 8 6 . 0 / 2 1 1 1 7 4 . 0 / 1 1 1 2 . 1 6 2 . 0 / 1 _ 1 _ 1 1 1 _ 1 _ 1 5 0 . 0 / 1 2 1 1 " " l l 1 1 " . " ' 1 3 8 . 0 / 1 1 4 1 1 2 6 . 0 / 1 12 1 2 1 • 1 1 1 1 4 . 0 / 1 2 1 1 1 1 0 2 . 0 2 2 1 2 . 1 1 1 1 9 0 . 0 0 / 1 3 1 3 2 1 1 2_ 1 1 , _ _ 7 8 . 0 0 / . . 2 2 3 , 1 ' " 1 ' " " l - " " " " 6 6 . 0 0 / 1 3 1 2 5 3 4 1 1 1 5 4 . 0 0 / 1 I 5 2 1 11 1 1 4 2 . 0 0 / 2 2 4 1 3 1 1 1 3 0 . O F / 2 5 1 3 I I 1 1 1 8 . 0 0 / 1 6 3 4 1 3 1 6 . 0 0 0 / - 6 . 0 0 0 / - 1 8 . 0 0 - 3 0 . 0 0 - 3 0 . V. 3 0 . 0 0 0 0 . 0 0 1 5 0 . 0 2 1 0 . 0 2 7 0 . 0 0 1 STANCE BC T U F E N S 1 A S H F S f N THE X - A X I S I S 3 . 0 0 0 * « DURATION (cseo) Figurejf, 2. Regression of Within-Utterance Range onDuration • Utterances with One Middle-Point: A*i5 •) i ••' !>.-> C ' l U S T C ' l r r r E E A T I C F P R P R S T O FRR S T O FRP S T O FRR RSO V A ~ V A P A R ( H I ( R ) ( A l ( R I ( Y l UA'.r.z n i j o 4 1 . 5 7 l . i i ) 7 4 6 . 8 3 0 . 0 0 0 0 5 . 3 2 5 0 . 1 4 7 1 5 1 . 9 5 0 . 1 9 3 7 T h = » . • • ANO " • " A t T U S 5 U TO P L O T THE R E G R E S S I O N I I N F : THE " * • • I S U S E D WHEN A PLCT P C I N T COVERS D A T A P O I N T S ' 1 0 . 2 4 C . 0 y = 13.97 + 1.007x 1 ' ° - r . 0 > • ) . • * '• / / / / _/ 7 / / / / / / / / l / l / . i .. / l / / l l 1 I . . . i f . . . . 1 1 2 1 1 2 ? 2 1 ' 2 4 2 1 3 1 1 1 / 2 i » r i i / 4 5 1 1 1 1 / / _/ _ _ f~ " " "" " "" " ' " " " ' ii\iiiiiiiii\iininii\iiiiiiiii\iiiiiini\iiiiiiiii\iiiiiiiii\iiiifiiii\iiiii/iii\iiiiiiiii\iiiiiiiii\ ' • . < ! ' 3 l . f i ' . 7 . 0 0 R 3 . 0 0 1 0 9 . 0 1 3 5 . D I S T V i r i n r i w r r M 51 A S H E S ON THE X - A X I S I S 1 . 3 0 0 3 1 0 . 0 3 0 3 . 0 2 " 6 . 0 2 8 9 . 0 2 8 2 . 0 2 7 5 . 0 2 6 8 . 0 2 6 1 . 0 2 5 4 . 0 2 4 7 . 0 2 4 0 . 0 2 3 3 . 0 2 2 6 . 0 ? I < ) . 0 2 1 2 . 0 2 0 5 . 0 1 9 8 . 0 1 1 1 . 0 1 8 4 . 0 1 7 7 . 0 1 7 0 . 0 1 6 3 . 0 1 5 6 . 0 1 4 9 . 0 1 4 2 . 0 1 1 5 . 0 1 2 3 . 0 1 2 1 . 0 1 1 4 . 0 1 0 7 . 0 1 C 0 . 0 9 3 . 0 0 8 6 . 0 0 7 9 . 0 0 7 2 . 0 0 6 6 . 0 0 5 8 . 0 0 5 1 . 0 0 4 4 . 0 0 3 7 . 0 0 3 0 . 0 0 2 3 . 0 0 " 1 6 . 0 0 9 . 0 0 0 2 . 0 0 0 - 5 . 0 0 0 - I 2 . 0 0 - 1 9 . 0 0 - 2 6 . 0 0 " - 3 3 . 0 0 - 4 0 . 0 0 r-o r—1 on * • DURATION (cseo) rigure.H. 3. Re_re3_ion_of Within-utterance on Duration^— Utterances_ with One Middle-Point: AMR C" " ' r"r n "inTi C V N . r c n t r r " F F A T I O " " F P B C I H s f n E R R ' ~ S T O ' F R R " S T C F R R " R S Q V A « V A O A )\ ( B ) ( 8 ) ( A ) ( B ) ( Y ) | P J » ' « O U R ' . 7 . 1 7 0 . 6 4 2 6 3 8 . 1 3 0 . 0 0 0 0 4 . H 1 8 0 . 1 0 3 5 4 8 . 9 8 0 . 1 2 9 5 I F F " . " A C O ••*'• A " F I J S . C T O Pi i n T H E R E O / P F S S I O N L I N E ! T H E " * " I S U S E D W H E N A P L O T P C I N T C O V E R S O A T A P O I N T S 2 - 3 0 . 1 - 1 2 9 0 . 0 / y = 4 7 . 1 7 * 0 . S 4 2 6 X 2 8 4 . 0 / 2 7 8 . 0 / 2 7 2 . 0 / 1 2 6 6 . 0 / . _ 2 6 0 . 0 / - - - - - 2 5 < 1 _ 0 / 2 4 8 . 0 / 2 4 2 . 0 / 1 2 3 6 . 0 2 3 1 . C - 2 3 0 . 0 / 1 2 2 4 . 0 / 1 2 1 8 . 0 / 1 2 1 2 . 0 / 1 2 0 4 . 0 / 1 1 2 0 0 . 0 _ / . 1 9 4 . 0 X I . 1 8 8 . 0 " / 1 " 1 8 2 . 0 £ / 1 1 1 . 1 7 6 . 0 " " 1 7 ' . 0 - 1 1 7 0 . 0 / 1 1 1 - . 1 6 4 . 0 / 1 1 1 1 5 8 . 0 / 1 1 1 1 , H 2 . 0 / " i "2 ' * i r i46.o / . 1 4 0 . 0 / 1 1 1 3 4 . 0 / 1 1 1 . I 1 2 8 . 0 / 1 1 1 2 1 1 2 2 . 0 / 1 1 3 1 1 1 . 1 1 6 . 0 1 1 0 . " - 1 1 2 1 1 1 1 1 1 1 0 . 0 / 1 1 2 1 1 1 . 1 0 4 . 0 / 1 1 1 1 9 8 . 0 0 / 1 2 2 1 . 1 2 9 2 . 0 0 / 1 2 1 1 1 8 6 . 0 0 / 1 1 3 1 1 1 1 2 . 1 1 8 0 . 0 0 / ' 2 2 1 1 1 7 4 . 0 0 / 2 1 3 2 1 * 1 1 1 6 8 . 0 0 / 1 1 1 4 2 1 1 1 6 2 . 0 0 I 1 . 1 3 1 1 1 2 1 1 5 6 . 0 0 5 0 . ' f - . 3 2 1 5 1 3 1 1 5 0 . 0 0 / . 1 2 4 _ 2 1 1 _ 4 4 . 0 n / ' " 2 1 1 5 " ' l - 2 1 1 " 1 - - - - - - " 3 8 . 0 0 / . 1 4 1 6 1 1 1 1 3 2 . 0 0 / ' 1 1 1 1 2 1 1 1 1 1 2 6 . 0 0 / 1 3 2 1 1 3 2 2 0 . 0 0 / 1 4 1 1 ? J 1 4 . 0 0 / 1 2 3 1 1 1 _ _ _ 8 . 0 0 0 / "" rrs'T ' i ' ~ " " " " ' 2.000 / - 4 . 0 0 0 - I O . ' . ' 1 - - 1 0 . 0 0 i i \ i i i i i i i i i \ i i i i i i i i i \ i i i i i i i i i \ i i i i i i i i i \ i i i i i i u i \ iiiiiiiiiMiiiiiiiiMiiiiiiii\iitiiiiiiMiiumi\ - 2 . 0 . 1 ' / 3 0 . On 8 0 . 0 0 1 3 0 . 0 1 8 0 . 0 2 3 0 . 0 0 1 STANCE » f . r w S * . | S I . A S H F S CU T F F X - A X I S I S 2 . 5 0 0 x = DUWION (csec) UE.P i N l VAR VAR RANGE CUR THE " . " AND Figure H.4. Regression of Within-Utterance Range on Duration — Utterances with One Middle-Point:_ JLR CONST C U C F F F i l AT 11] F P R O B STO ERR STO ERR STO E 1 R R S C A II (It) (Bl (A) IB) m 4 3 . 1 7 1 . 0 3 6 2 6 . 3 3 O.OCOO 8 . 0 9 7 0 . 2 0 1 9 1 0 0 . 7 • " A ^ S USCO to P L O T THE R E G R E S S I O N L I N E ; THE AN I N T E G E R " l " , H E I W E E N I A NO 9 , R E P R E S E N T S A P P R O X I M A T E L Y " 0 " R E P R E S E N T S 1_UK. FEWER UA.IA_P0INIS;. .__._.RE|>RES_NIS_. " • " I S USEO WHEN A P L O T P O I N T C O V E R S 3 * 1 U A T A P O I N T S _ _ 2 9 . . O R . M O R E . O A T A - P . O I N L S 0 . 0 5 3 * D A T A P O I N T S 1 5 6 0 . 1 2 4 0 . 9 2 0 . 0 6 C O . 0 2 8 0 . 0 / / / / / / / / / .... / / / / / / . . . . / -/ / / / . . / / / / / / /._ / / / / / . . / / / / __/... / / / / / I . I I y = 4 3 . 1 7 + 0 . y = 4 3 . 1 7 • 1 . 0 3 6 X 0 _ I 1 0 U 2 4 2 2 3 . / 6 6 2 1 Q . C 0 u... 0 C 0 _ ] 0 . . 1 0 0 - 4 0 . 0 0 //I/////////1 III it tn i\i 11 in i/i I iii/ii/i/1 mi 11 in i in II in 111 II i II in i i/ii/iii/i II i in in 11 it II II 111 5 . C C 0 4 1 . 0 0 7 7 . 0 0 1 1 3 . 0 1 4 9 . 0 1 8 5 D I S T A N C E B a i W E E N . S L A S H E S . U N - I H E _ X - A X I . S _ I 5 l.BOQ. . „ _ . 1 5 6 ' J . 1 5 2 8 . 1 4 9 6 . 1 4 6 4 . 1 4 3 2 . 1 4 0 0 I 3 6 b . 1 3 3 6 . 1 3 0 4 . 1 2 7 2 . 1 2 4 0 . 1 2 3 H . 1 1 7 6 . 1 1 4 4 . 1 1 1 ? . lOtiO. 1 0 4 8 . 1 0 1 6 . 9114.0 9 5 2 . 0 9 2 0 . 0 8 8 8 . 0 8 5 6 . 0 . 8 2 4 . 0 7 9 2 . 0 7 6 0 . 0 7? r t . 0 6 9 6 . 0 6 6 4 . 0 6 3 2 . 0 6 C 0 . 0 5 6 B . 0 5 3 6 . 0 5 0 4 . 0 4 7 2 . 0 4 4 0 . 0 4 0 8 . 0 3 7 6 . 0 3 4 4 . 0 3 1 2 . 0 2 3 0 . 0 . . 2 4 8 . 0 2 1 6 . 0 1 8 4 . 0 1 5 2 . 0 1 2 0 . 0 8 8 . 0 0 5 6 . 0 0 2 4 . 0 0 - 8 . 0 0 0 - 4 0 . 0 0 . 0 x = DURATION (csec) n r i ' I M ) VJ.» V A » P A N r . t OMR i > F « . » AHO _ . ^ i _ ^ r - - H i - - - _ ? c 8 ~ « o _ o n . _ o f W i t h i n - U t t e r a n c o R a n g e o n D u r a t i o n — U t t e r a n c e s w i t h One M i d d l e - P o i n t . : "car.T ' enrrr F R A T I O F P P C B S T D C P R S T D E R R S T C F R R "" A .". ( R l I B ) ( A ) I B ) I V ) I - . * - 1 . 0 3 0 l O . ' T 0 . 0 0 1 6 1 7 . B 7 0 . 3 1 7 0 1 3 6 . 5 " A P F i / S F O TfJ P L O T THF R F C F F S S I O N L I N E ; THE " • " I S U S E D W H E N A P L O T P C I N T C O V E R S D A T A D A E R S Q " 0 . 0 6 0 2 P O I N T S 7 / 0 . 75.45 + 1 .030X 4 0 r ' • •". 4 4 0 . 0 1 1 J P " . 0 l ? - . o 1 / / / / / _ / l" I II C I S 1 1 1 1 1 ] 2 1 1 1 1 4 . 2 I 2 '" l " 1 2 3 1 1 2 2 1 2 2 2 2 3 4 3 6 6 B 2 2 2 3 3 ? 1 I * 1 1 1 I 1 1 1 1 3 1 1 ! 1 1 \l III1111 l\l 111II111 \ 111111111 \ 11111II11 \ l l l l l l l l l \ l l l l l l l l l \ l l l l l l l l l \ I I I I I I U I \ l l l l l l l l l \ l l l l l l l l l \ 5 . C < r 3 0 . ( 0 7 3 . 0 0 1 0 7 . 0 1 4 1 . 0 1 7 5 . 141:0'- I T I W I ' l ' l 51 A . H I " ' . I N TI IF X - A X I S I S 1 . 7 0 0 7 6 0 . 0 7 4 4 . 0 7 2 8 . 0 7 1 2 . 0 6 " 4 . 0 6 8 0 6 6 4 6 4 8 6 3 2 6 1 6 6 0 0 5 8 4 . 0 5 6 8 . 0 5 5 2 . 0 5 3 6 . 0 5 2 0 . 0 5 0 4 . 0 4 8 8 . 0 4 7 2 . 0 4 5 6 . 0 4 4 0 . 0 4 2 4 . 0 4 0 8 . 0 3 1 2 . 0 3 7 6 . 0 1 6 0 . 0 3 4 4 . 0 3 2 B . 0 3 1 2 . 0 2 9 6 . 0 2 8 0 . 0 2 6 4 . 0 2 4 8 . 0 2 3 2 . 0 2 1 6 . 0 2 0 0 . 0 1 8 4 . 0 1 6 H . 0 1 5 2 . 0 1 3 4 . 0 1 2 0 . 0 1 0 4 . 0 8 8 . 0 0 7 2 . 0 0 5 6 . 0 0 4 0 . 0 0 2 4 . 0 0 B . 0 0 0 - 8 . 0 0 0 - 2 4 . 0 0 - 4 0 . 0 0 0 ro H CO x = DURATION ( c s e c ) _ Figure H.6, Regression of Within-Utterance Range on Duration:— Utterances with One Middle-i oint: MJK * ' i•>•!•" ~ i'to rrf.v» ' cnirr f A t i n F I - R U R S T O I R » S T O F R R S T O F R R " R S O V I ! ' V A ! . A |> ( R ) ( R I ( A ) ( 0 ) ( Y ) p v r t r u t 7 H . I 7 1.->]r,7 0 . 2 1 3 8 1 0 . 3 2 0 . 2 5 7 8 8 2 . 7 3 0 . 0 0 7 8 r n ' " . " / " i n ••»" f->i\ i r . r o T O P I o i T o r prr.ors^ inN i I ^ F : T M T ••*•• is U S F O M I F N A P I D T P O I N T C O V E R S D A T A P O I N T S A M l O T F O r i - ••!•>,niTwr^'J 1 A N O o, R F P R E S F M T S A P P R O X I M A T E L Y 2»I D A T A P O I N T S .. B h P - r s r f - T S 1 OR F F W T P O A T A P O I N T S ; " A " P F P P F S I N T S 2 0 O R M O S T D A T A P O I N T S 7 ' . ; . 0 - 0 7 3 0 . 0 y - 78.87 * 0.3197X ] ] ^ \ % I 6 8 5 . 0 / ft 7 0 . 0 / _ * 5 S . O 7" " " " " " ~ 6 4 0 . 0 / 6 2 5 . 0 / 6 1 0 . 0 / 5 9 5 . 0 5 > e . 0 - 5 8 0 . 0 _ l o __. _ 1 6 5 . o " ~ ' . - - 6 5 0 . 0 / O 5 3 5 . 0 / 5 2 0 . 0 / 6 0 5 . 0 / 4 9 0 . 0 / 4 7 6 . 0 / " ~ " " - - - - 4 6 0 . 0 / 4 4 5 . 0 4 3 9 . 0 - 4 3 0 . 0 / 4 1 5 . 0 / 4 0 0 . 0 / 3 8 5 . 0 ' / - - _ . 3 7 0 . 0 / 3 5 5 . 0 / 3 4 0 . 1 / 3 2 5 . 0 / 3 1 0 . 0 I 2 9 5 . 0 * > P " i " . 0 " - ~ " " " 2 8 0 . 0 / 2 6 5 . 0 / 2 5 0 . 0 / 0 2 3 5 . 0 / 1 n o 2 2 0 . 0 / 0 l. 0 2 0 6 . 0 / 0 0 1 9 0 . 0 / 0 0 0 1 7 5 . 0 / 9 0 1 1 6 0 . 0 / 1 0 1 1 1 1 1 0 - 1 4 5 . 0 1 3 9 . 3 - 1 1 0 0 0 0 0 . 1 3 0 . 0 / 1 . 0 0 0 0 0 0 0 . 1 1 5 . 0  I 1     !\ 1 1 0 0 2 0 1 f > 1 1 0 0 0 1 1 n 0 1 / 1 ! 1 c. r,    1 0 0 l i O . O / * 9 2 * 1 0 2 0 1 1 0 0 8 5 . 0 0 / 9 9 6 1 ? n    1 1 0 7 0 . 0 0 / 2 9 2 'J   5 5 . 0 0 / l - i 4 1 9   0 O 4 0 . 0 0 I ') 1 2 _J 1 9 _ _ _ o _ _ 2 5 . 0 0 / " " i ?' 1 1 i 0 " " ' ~ " " " " " " 1 0 . 0 0 / 0 - 5 . 0 0 0 - 2 0 . 0 0 i i \ i i i i n i i i \ i i i i i i i i i \ i i i i i u i i \ i i i i i i i i i \ u i u / i u \ i i i i i n i i \ i i i i i i i i i \ i i i i i i i i n i i i i i i i i i \ i i i i i i i i i \ - " . ' ' 37,Of.) 6 4 . 0 0 9 6 . 0 0 1 2 8 . 0 1 6 0 . 0 I) 1 r W.f.'O'' P F T w r r * ! SI.AS ' II 5 ON TMF X - AX I S I S 1 .61 (1 x = DURATION (csec) . Figure H . 7 . Regression of Within-Utterwice Range on Duration ~ Utterances with two Middle-Points: CAB ! \ i > CFNST C O F F F FP AT 10 FPROR STD ERR S T D ERR S T C ERR RSQ VA."- A R ( R > ( R ) ( A ) ( R ) ( Y l Cuo 5 7 . 9 0 0 . 5 . - 3 ' . 6 . C 1 5 0 . 0 4 2 8 2 9 . 4 3 0 . 2 2 9 f t 5 4 . 1 A 0 . 4 6 2 2 . ' • A f l O » » • • APE U S F P TO PLOT THE R E G R E S S I O N L I N E : THF " * " I S USED WHEN A P L O T P O I N T C O V E R S D A T A P O I N T S 1 2 6 0 . 0 y = 9 7 . 9 0 + 0 . S 6 3 6 X . 2 5 5 . 0 2 5 0 . 0 2 4 5 . 0 2 4 0 . 0 • 2 3 5 . 0 2 3 0 . 0 2 2 5 . 0 1 2 20 . 0 2 1 4 . 0 2 1 0 . 0 • 2 0 5 . 0 . - ' 2 0 0 . 0 1 9 5 . 0 1 . 1 9 0 . 0 1 1 R 5 . 0 1 8 0 . 0 1 7 5 . 0 " " 1 7 0 . 0 1 6 5 . 0 1 1 6 0 . 0 1 5 5 . 0 1 1 5 0 . 0 . _ _ _ 1 4 5 . 0 " " " " " " " " " " 1 4 0 . 0 1 3 5 . 0 1 3 0 . 0 1 2 5 . 0 1 2 0 . 0 1 1 1 5 . 0 " " " " " " " " ' " " " "" "' n o . o 1 0 5 . 0 . . 1 0 0 . 0 9 5 . 0 0 • 9 0 . O n _ _ R 5 . 0 0 i " '" ' " " " ' " ' " " " " " ' 8 0 . 0 0 7 5 . 0 0 7 0 . 0 0 6 5 . 0 0 6 0 . 0 0 __ _ _ 5 5 . 0 0 • ~ ~ " " 5 0 . 0 0 4 5 . 0 0 1 4 0 . 0 0 3 5 . 0 0 3 0 . 0 0 2 5 . 0 0 2 0 . 0 0 1 5 . 0 0 1 0 . 0 0 //1 / / / / / / /n\ II II nm I iiiuiui1 in i mi 11 n in II 11\ 111111111111 im II i\ II i in m 1111 II i II n mi i mi I - 2 ' - . 4 0 . n i 1 0 0 . 0 1 6 0 . 0 2 2 0 . 0 2 8 0 . 0 0 1 STANCE I I T T H F E N S L A S H E S I N TEG X - A X I S I S 3 . 0 0 0 x = DURATION Ccsec) r _ Figure H.8. Regression of Within-Uttorance Range on Duration — Utterances with Two Middle-Points:_ AMG " ' ' | . " f i r i r ! ' ; I 001 -11 - F M A T i n h M C B S T D f.KH S T D FRO S T D FRR R SO V » = V A r - .'. « ( R l ( R l ( A l ( R l I Y ) PA (.'-.'•- ou<-' I I S . i 0 . 2 7 4 4 0 . 7 7 9 8 0 . 3 9 2 7 2 4 . 9 3 0 . 3 1 1 0 4 6 . 0 4 0 . 0 4 1 5 THF •' . " . ' . ' I 'V ftut i , s r n TO P | i ) T TMT P F O l . F S S I O K L I M f i THF " * " I S U S F O WHEN A P L O T P O I N T C O V F R S D A T A P O I N T S 2 _ ' -g ? - 1 5 4 . 1 •4 2 . < 1 1 y = 11S.5 + 0.2746X 226.0 222 .4 218.8 215.2 211 .6 20R.0 204.4 200.8 197.2 193.6 1 90.0 1R6.4 182.8 179.2 175.6 172.0 168.4 1 64.8 161.2 157.6 154.0 150.4 146.8 143 1 39 136 132 12ft 125 121 2 ,6 O 4 8 2 6 118.0 1 1 4 .4 1 11.R 107.2 1 03 .6 100.o 9 4 . 40 92.80 B9. 20 8 5.60 82.00 78. 40 74. 80' 71 .20 67 . 60 64.00 6 0 . 4 0 56. 80 53.20 49.60 46.00 ii\iiiiiiin\iiiiiiiii\iiiii/iii\iiniiiii\iiiuiiii\iiiiiiiii\iiiiiiiii\iiiiiiiii\iiiiiiiu\iuiiiiii\ ? ' i . ' i 3 4 A . r o 7 6 . 0 0 1 0 4 . 0 1 3 2 . 0 1 6 0 . 0 HISTA'l.F ' I ' -HJFI M SI A SMI S UN THF X-AXIS IS 1.400 x = DURATION (csec) I E " p i n V ! f V A< P A N G * nu" TEE " . " A N O Figure I I .9. Regression of Within-JJttprance Ran£o on Duration — Utterances with Two Miildln-Pointa: AMR " r r ' N S T C O I E E F P A T i n F P R O B STO F R R " S T D F P R S T O E R R R S O A n i n ) ( B ) ( A I ( 0 ) ( Y ) 5 5 . 5 7 0 . 7 1 U 2 8 . 4 2 0 . 0 0 0 0 1 2 . 3 7 0 . 1 3 3 4 4 7 . 9 9 0 . 2 4 4 1 • A l> I I S F O TO, l>l U T THE P . E G E E SS I ON L I N E ; T H E " « " I S U S E O W H F N A P L O T P O I N T C O V E R S O A T A P O I N T S 270.n 2 2 " . n I j . i " 1 2' y = S5.57 • 0.711_x 7 f . C C 1 1 I 1 1 1 2 0 . OO 2 7 0 . 0 2 6 5 . 0 2 6 0 . 0 2 5 5 . 0 7 4 0 . 0 2 4 5 . 0 2 4 0 . 0 2 3 5 . 0 2 3 0 . 0 2 2 5 . 0 2 2 0 . 0 2 1 5 . 0 2 1 0 . 0 2 0 5 . 0 2 0 0 . 0 1 9 * . 0 1 9 0 . 0 1 8 5 . 0 1 8 0 . 0 1 7 5 . 0 1 7 0 . 0 1 6 5 . 0 1 6 0 . 0 1 5 5 . 0 1 5 0 . 0 1 4 5 . 0 1 4 0 . 0 1 3 5 . 0 1 3 0 . 0 1 2 5 . 0 1 2 0 . 0 1 1 5 . 0 I 1 0 . 0 1 0 5 . 0 1 0 0 . 0 9 5 . 0 0 9 0 . 0 0 3 5 . 0 0 8 0 . 0 0 7 5 . 0 0 7 0 . 0 0 6 ^ . 0 0 6 0 . 0 0 5 5 . 0 0 5 0 . 0 0 4 5 . 0 0 4 0 . 0 0 3 5 . C O 3 0 . 0 0 2 5 . 0 0 2 0 . 0 0 ll\IIIIIIIU\lllllllll\lllllllll\lllllllll\lllllllll\lllllllll\lllllllll\lllllllll\lllllllll\llllllltl\ 3 5 . ' ' 0 7 | . 0 0 1 0 7 , 0 1 4 3 . 0 1 7 9 . 0 2 1 5 . 0 U I S T A'H'.i I ' . F r w C I M S L A S H E S UN I H L X - A X I S I S 1 . 8 0 . 0 ro ro ro X = DURATION (csec) Figure H.10. Regression of Within-Utterance Range on Duration — Utterances with Two Middle-Points: JLR^ HK-P I M ) C O N S T CCF.FF F K A T I I I F P R U l l S T O ERR STO CRR STD CRR RSCl V A R V A R A H ( I I ) ( I D ( A ) ( H ) ( Y ) R A N - E CUS 51.71 I . O i l 1 2 . 5 9 0 . 0 0 0 8 2 4 . 7 1 0 . 2 8 5 0 9 2 . 7 6 0 . 1 5 0 6 THE " . " A NO " * " ARE U S F C TO PLOT THE R E G R E S S I O N L I N E ) THE " • " I S U S E O WHEN A P L O T P O I N T C O V E R S D A T A P O I N T S 5 6 0 . 0 4 5 0 . 0 B 3 4 0 . 0 / / / / / / / / . / / / / / / / _. / / / / . / _.. / / / / / - V .... 2 3 0 . 0 1 2 0 . 0 y = 59.77 t l.Ollx 1 L. 2 — 1...-1 0 . 0 0 5 6 0 . 0 5 4 9 . 0 5 3 8 . 0 5 2 7 . 0 5 1 6 . 0 5 0 5 . 0 4 9 4 . 0 4 8 3 . 0 4 7 2 4 6 1 4 5 0 . 4 3 9 4 2 « 4 1 7 4 C 6 3 9 5 . 0 3 8 4 . 0 3 7 3 . 0 3 6 2 . 0 3 5 1 . 0 3 4 0 . 0 3 2 ) - J 3 1 8 . 0 3 0 ^ . 0 2 9 6 . 0 2 8 5 . 0 2 7 4 . 0 2 6 3 . 0 2 5 2 . 0 2 4 1 . 0 2 3 U . 0 2 1 9 . 0 2 0 8 . 0 1 9 7 . 0 1H 6 . 0 1 7 5 . D 1 6 4 . 0 1 5 3 . 0 1 4 2 . 0 1 31 . 0 1 2 0 . 0 1 0 9 . 0 9 8 . 0 3 8 7 . 0 0 7 6 . 0 0 6 5 . 0 0 5 4 . 0 0 4 3 . 0 0 3 2 . 0 0 2 1 . 0 0 1 0 . 0 0 / / I / / / / / / / / / i mi i ii i i i i i III i u ui HUM mi mi 11 ii ii i III 11 III ii III I t u n it it1 III mi in u i nm 11 1 C . 0 0 3 8 . 0 0 6 6 . 0 0 9 4 . 0 0 1 2 2 . 0 1 5 0 . D i S T A . - J C c U E T w E L N S L A S H E S . O M . I H E _ J C r A X l S I S . 1 . 4 C C . . . .'. CO X = DURATION (csec) r i MfJ - t t > r , r Figi___H.ll._ Regression of_Within-Utterance Range on Duration »- Utterances with Two Middle-Points; DAT, Tf/> rT ' - ' . T " c m i " ' h A T i n " r p f t r m " ~ ~ S T O " F P . R S T O " F R * STO C R R ' RSQ V A R A M ( R) ( B I ( A I I R) (YI H I R 1 2 6 . 9 - 0 . 1 6 ] n n - o i 0. 1 6 9 6 0 - 0 2 C . 9 1 1 1 3 8 . 3 5 0 . 3 9 1 0 7 6 . 4 7 0 . 0 C 0 1 • . " AMD " » • • M ' F U S f r " TO P l n T T I I F P F G R F S S I C N L I N F ; T H F " * • ' I S I I S F O W H F N A P L O T P O I N T C O V E R S O A T A P O I N T S y s 126.9 - 0.01610X 2 2 0 . ' 5 lfto.o l l 2 B 0 . 0 2 7 4 . 0 2 6 8 . 0 2 6 2 . 0 2^6.0 2 5 0 . 0 2 4 4 . 0 2 3 8 . 0 2 0 2 . 0 2 2 6 . 0 2 2 0 . 0 2 14 . 0 " " 2 0 n . O 2 0 2 . 0 1 0 6 . 0 1 9 0 . 0 1 8 4 . 0 1 7 8 . 0 1 7 2 . 0 1 6 6 . 0 1 6 0 . 0 1 5 4 . 0 1 4 8 . 0 1 4 2 . 0 1 0 6 . 0 1 3 0 . 0 1 2 4 . 0 11R . 0 1 1 2 . 0 1 0 6 . 0 ' 1 O i . P 9 4 . 0 0 8 3 . 0 0 8 2 . 0 0 7 6 . 0 0 7 " . 0 0 6 4 . 0 0 5 8 . 0 0 5 2 . 0 0 4 6 . 0 0 4 0 . 0 0 3 4 . 0 0 2 8 . 0 0 2 2 . 0 0 1 6 . 0 0 1 0 . 0 0 4 . 0 0 0 - 2 . 0 0 0 - 8 . 0 0 0 - 1 4 . 0 0 - 2 0 . 0 0 u\niniiii\iiuiuii\iiiiiiiii\iiuiiiii\iiitiiiii\iiiiiiiii\iiuiiiii\iiiiiiiii\iiiiiiiii\iiiiiiiii\ 7 0 . 0 1 6 8 . 0 0 8 6 . 0 0 1 1 4 . 0 1 4 2 . 0 1 7 0 . 0 " I S T A N C F " f l W I F ' l S I . A S u r s ON T I I F X - A X I S I S 1 . 4 0 0 to 4=-x = DURATION (csec) „F_gureJH_12. Regression of WithirwUtterance Range on Duration — Utterances with Two Middlc-PointG: MJK i-tp i'»i<i V.rf:«u c n r f r ~ " F i ' A T i n F P R F I R S T n F R R S T D F R R S T D F R R R S Q VAR V A F A p ( R | ( R | ( A l ( R I I Y ) P A ' . r 1 0 " . R > 0 . 7 7 1 " A . 3 7 7 O . O 3 0 7 ? 7 . 6 6 0 . 3 6 9 5 12.fi 0 . 0 8 5 2 T i - r » . " AND " * " A T . I J S F O TO P L O T T H E R E G R E S S I O N L l N F ; T H F " » " I S U S E D W H E N A P L F T P O I N T C O V E R S D A T A P O I N T S 7 0 0 . 0 • f O . r o 1 1 yy= 100.5 + 0.7.730X 1 1 1 1 1 . 1 1 1 1 1 - 1 -ii\iiiiiiiii\iiiiiun\iiiiiiiii\iiiuiiii\iiuiiiii\iitiiiiii\iiiiiiiii\iiiitiiii\iiiiiiiii\iiiuiiii }i.''< < R . r o 6 6 . o n 9 A . O 0 1 2 2 . 0 . 0 H T A M C r . P f T W F r N , I . A S " . S ' I N THF X - A X 1 < I S U « x = DURATION (csec) 4 0 0 . 0 4 R 0 . 0 4 7 0 . 0 4 6 0 . 0 4 5 0 . 0 4 4 0 . 0 4 3 0 . 0 4 2G . 0 4 1 0 . 0 4 0 0 . 0 3 9 0 . 0 3 H 0 . O 3 7 0 . 0 1 6 0 . 0 3 5 0 . 0 3 4 0 . G 3 3 0 . 0 3 ? 0 . C 3 1 0 . 0 3 0 0 .r 2 9 0 . 0 2 R 0 . 0 2 7 0 . 0 2 6 0 . 0 2 4 0 . 0 2 4 0 . 0 2 3 0 . 0 2 2 0 . 0 2 1 0 . 0 2 0 0 . 0 1 9 0 . 0 1 H 0 . 0 1 7 0 . 0 1 6 0 . 0 1 5 0 . 0 1 4 0 . 0 1 < 0 . 0 1 2 0 . 0 1 1 0 . 0 1 0 0 . 0 0 0 . 00 R O . 0 0 7 0 . 0 0 ' 6 0 . 0 0 4 0 . 0 0 4 0 . 0 0 3 C . 0 0 2 n . 0 n 1 0 . 0 0 - 0 . 0 - 1 0 . 0 0 I 1 5 0 . 0 r o r o c n 

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