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Speech errors and segment duration : an investigation of word-initial/sp, st, sk/-clusters under conditions… Pyplacz, Verna 1976

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SPEECH ERRORS AND SEGMENT DURATION: AN INVESTIGATION OF WORD-INITIAL  /sp, s t , sk/-CLUSTERS  UNDER CONDITIONS OF RAPID REPETITION  by Verna Lynne P y p l a c z B.A., U n i v e r s i t y o f B r i t i s h Columbia, 1974  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES Department o f P a e d i a t r i c s D i v i s i o n o f A u d i o l o g y and Speech S c i e n c e s  We accept t h i s t h e s i s as conforming to the r e q u i r e d  standard  THE UNIVERSITY OF BRITISH COLUMBIA May, 1976 (c)  Verna Lynne P y p l a c z , 1976  In p r e s e n t i n g t h i s  thesis  an advanced degree at the I  Library shall  f u r t h e r agree  for  fulfilment of  the requirements f o r  the U n i v e r s i t y of B r i t i s h Columbia,  make i t  freely available  that permission  for  I agree  r e f e r e n c e and  f o r e x t e n s i v e copying o f  this  that  study. thesis  s c h o l a r l y purposes may be granted by the Head of my Department or  by h i s of  in p a r t i a l  this  written  representatives. thesis  It  is understood that copying or p u b l i c a t i o n  f o r f i n a n c i a l gain s h a l l  not be allowed without my  permission.  Verna Lynne P y p l a c z  Paediatrics D i v i s i o n o f A u d i o l o g y and Speech S c i e n c e s Department of  The  U n i v e r s i t y of B r i t i s h  2075 Wesbrook Place Vancouver, Canada V6T 1W5  Date  1 4 t h May  1976.  Columbia  ABSTRACT Speech e r r o r s , o r " s l i p s o f t h e tongue", have been studied  i n attempts t o u n d e r s t a n d t h e speech p r o d u c t i o n  process, to investigate  p h o n o l o g i c a l u n i t s and r u l e s , and  to p r o v i d e i n s i g h t s i n t o h i s t o r i c a l l i n g u i s t i c change. The  p r e s e n t study examines speech e r r o r s and t h e i r r e l a -  t i o n t o segment d u r a t i o n s i n w o r d - i n i t i a l / s p , s t , sk/c l u s t e r s produced under r a p i d r e p e t i t i o n c o n d i t i o n s s i x adult native  by  speakers o f E n g l i s h .  F i f t y p e r c e n t o f t h e e r r o r s produced c o u l d be c l a s s i f i e d as r e p e t i t i o n e r r o r s ; these were examined f o r d u r a t i o n i n t h e i n i t i a l c l u s t e r s , b o t h e r r o r and c o r r e c t e d General r e s u l t s f o l l o w i n g (1)  from a n a l y s i s  productions.  o f t h e d a t a were:  E r r o r c l u s t e r s and t h e i r component segments were con-  s i s t e n t l y l o n g e r i n d u r a t i o n than t h e i r subsequent and immediate (2)  corrections. The c l u s t e r s /sp/ and /sk/ a r e l o n g e r than / s t / , w h i c h  may be a t t r i b u t a b l e t o t h e f a s t e r moving, more h i g h l y v a t e d tongue t i p m u s c u l a t u r e i n v o l v e d Is/ (3)  inner-  i n the production of  and It/, compared w i t h t h e h e t e r o r g a n i c c l u s t e r s . The stop consonant i n a g i v e n c l u s t e r appears t o d e t e r -  mine t h e o v e r a l l c l u s t e r d u r a t i o n ,  since  the duration of / s /  remains f a i r l y c o n s t a n t i r r e s p e c t i v e o f c o n t e x t . I n l i g h t o f t h e r e s u l t s , i t was s p e c u l a t e d t h a t cessive  d u r a t i o n o f the c l u s t e r  t h e ex-  ( o r o f i t s component p a r t s )  v i o l a t e d a t i m i n g c o n s t r a i n t on the p r o d u c t i o n o f an u t t e r ance, n e c e s s i t a t i n g r e c a l i b r a t i o n and c o r r e c t i o n o f the error.  I t was  f u r t h e r i n f e r r e d t h a t feedback must be  present  i n o r d e r f o r the system to r e c o g n i z e the d u r a t i o n e r r o r , to compare i t w i t h p l a n n e d o u t p u t , and f i n a l l y t o execute  a  correction. Two  types of feedback were c o n s i d e r e d n e c e s s a r y f o r the  adequate f u n c t i o n i n g o f a speech p r o d u c t i o n model, w h i c h would a l s o a l l o w f o r speech p e r c e p t i o n :  (a)  a u d i t o r y feedback, w h i c h i s supplemented by p r o p r i o c e p t i v e feedback,  i n t h i s study. advocated  (b) i n t e r m i t t e n t  b o t h o f w h i c h a r e used i n p e r c e i v i n g  i n p u t ,:and m a n i p u l a t i n g o u t p u t . p l a u s i b l e account  continuous  Such a system p r o v i d e s a  o f speech e r r o r p r o d u c t i o n as d e s c r i b e d  The h y p o t h e s i z e d v a r i a b l e s e r v o m o n i t o r  system  here (and i n o t h e r s t u d i e s ) i n g e n e r a l p r o v i d e s  e f f i c i e n t means f o r p r o d u c i n g , m o n i t o r i n g and speech p r o d u c t i o n .  correcting  an  TABLE OF CONTENTS Page ABSTRACT  i i  TABLE OF CONTENTS  iv  LIST OF TABLES  v i  LIST OF FIGURES  viii  ACKNOWLEDGEMENTS  ix  DEDICATION  x  Chapter 1  INTRODUCTION  1  1.0  Introduction  1  1.1  L i t e r a t u r e Review:  1.2  F u n c t i o n a l Neuroanatomy o f Speech  3  1.21  C e n t r a l Nervous System  4  1.22  P e r i p h e r a l Nervous System  9  1.23  Sensory T r a c t s  H  1.24  Motor Systems  1.3  Introduction  3  .;  Feedback Mechanisms  12 :.  13  1.30  Introduction  13  1.31  The Gamma / S p i n d l e Motor System  14  1.32  A u d i t o r y Feedback  19  1.33  Summary  21  1.4  Speech E r r o r s  22  1.5  T i m i n g o f Speech  25  1.6  Models o f Speech P r o d u c t i o n  26  1.60  Introduction  26  1.61  Open-Loop Models  27  1.62  C l o s e d - L o o p Models  28  1.63  Summary and D i s c u s s i o n  30  iv  Page Chapter 2  STATEMENT OF THE PROBLEM  34  Chapter 3  METHOD  36  P i l o t Studies  36  3.11  P i l o t Study I  36  3.12  P i l o t Study II  37  3.13  Discussion  38  3.1  3.2  M a i n Study  3.3  A n a l y s i s o f Data  Chapter 4  ;.. .'  39 40  RESULTS  44  4.0  Introduction  44  4.1  C o n t r o l Group Data  47  4.2  Experimental  54  Chapter 5  Group D a t a  DISCUSSION  64  5.0  General Considerations  64  5.1  D i s c u s s i o n o f t h e C o n t r o l Group  65  5.2  Discussion of the Experimental  5.3  Theoretical Considerations  5.4  L i m i t a t i o n s of the Present  5.5  Summary and C o n c l u s i o n s  77  REFERENCES  80  APPENDIX A  85  APPENDIX B  86  APPENDIX C  87  APPENDIX D  88  v  Groups  67 71  Study  76  LIST OF TABLES Table 1  Page Types and Numbers o f Speech E r r o r s Produced by Each S u b j e c t  2  46  Types and Numbers o f R e p e t i t i o n E r r o r s Produced by Each S u b j e c t  3  46  C o n t r o l Group Data (Normal C o n v e r s a t i o n a l  Rate)  f o r W o r d - I n i t i a l Consonant C l u s t e r s /sp-/, / s t - / , /sk-/: Means and S t a n d a r d D e v i a t i o n s Durations 4  ( i n ms)  48  Summary o f A n a l y s i s o f V a r i a n c e :  C o n t r o l Group Data  -- C l u s t e r Segments and S u b j e c t s 4a  o f Segmental  =  .. 50  Newman-Keuls Summary T a b l e : C o n t r o l Group Data -C l u s t e r Segments and S u b j e c t s  5  Summary o f A n a l y s i s o f V a r i a n c e :  50 C o n t r o l Group Data  -- C l u s t e r s and S u b j e c t s 5a  . 51  Newman-Keuls Summary T a b l e : C o n t r o l Group Data -C l u s t e r s and S u b j e c t s  6  Summary o f A n a l y s i s o f V a r i a n c e : -- C l u s t e r Segments,  6a  51 C o n t r o l Group Data  One-Way C l a s s i f i c a t i o n  Newman-Keuls Summary T a b l e : C o n t r o l Group Data -C l u s t e r Segments  7  52  Summary o f A n a l y s i s o f V a r i a n c e :  C o n t r o l Group Data  --- C l u s t e r s , One-Way C l a s s i f i c a t i o n 7a  52  53  Newman-Keuls Summary T a b l e : C o n t r o l Group Data Clusters  53  vi  Table 8  Page Summary S t a t i s t i c s f o r Segmental and C l u s t e r D u r a t i o n s ( i n ms), i n S i x R e p e t i t i o n E r r o r Groups (termed E x p e r i m e n t a l Groups)  9  56  Summary o f R e p e t i t i o n E r r o r D a t a f o r E x p e r i m e n t a l Groups #2-#5: Segmental and C l u s t e r D u r a t i o n s ( i n ms)  ; . 61  vii  LIST OF FIGURES Figure 1  Page B l o c k Diagram o f I n s t r u m e n t a t i o n Used t o Produce Oscillograms  2  C o n t r o l Group Data:  42 Segment and C l u s t e r D u r a t i o n ;  Mean v a l u e s f o r each s u b j e c t 3  E x p e r i m e n t a l Groups #2-#5:  55 Segment and C l u s t e r  D u r a t i o n ; Mean v a l u e s f o r e r r o r and c o r r e c t productions 4  . 59  E x p e r i m e n t a l Groups #1 and #6:  Segment and C l u s t e r  D u r a t i o n ; Mean v a l u e s f o r e r r o r and c o r r e c t productions  60  viii  ACKNOWLEDGEMENTS I w i s h t o e x p r e s s my g r a t i t u d e t o a l l those who gave o f t h e i r time and energy i n h e l p i n g me complete t h i s t h e s i s . My thanks go e s p e c i a l l y t o : —  Dr. John G i l b e r t -- f o r h i s time and p a t i e n c e g i v e n as my supervisor;  —  Dr. D a l e K i n k a d e -- f o r t r a n s c r i b i n g d a t a , g i v i n g c r i t i c a l comments, and b e i n g k i n d enough t o s e r v e on my committee;  —  Dr. John D e l a c k  -- who doesn't s u f f e r f o o l s g l a d l y , f o r h i s t i m e , e f f o r t and n e c e s s a r y c r i t i c a l comments;  —  Ronnie S i z t o  -- f o r days (and n i g h t s ) spent p a t i e n t l y r u n n i n g , debugging, r e r u n n i n g and i n t e r p r e t i n g s t a t i s t i c a l programmes a t t h e e l e v e n t h hour;  —  Dr. Brenda F r a z e r - - f o r h e r s t a t i s t i c a l  —  Ingrid Jeffrey  -- f o r h e r a d v i c e on a n a l y z i n g o s c i l l o g r a m s ;  —  My S u b j e c t s  -- f o r t h e i r p a t i e n c e i n r e p e a t i n g "tongue-  advice;  twisters" ; —  My F a m i l y  -- who a r e always t h e r e when I need them;  —  My F r i e n d s i n t h e G r a d u a t i n g  ix  C l a s s o f '76.  This thesis i s dedicated t o the memory o f my Stan Pyplacz  father,  (1922-1975).  x  CHAPTER  1  INTRODUCTION 1. 0  Introduction A speech e r r o r can be, and has been, v a r i o u s l y  described  as a " s p o o n e r i s m " ( a f t e r the Revd. W i l l i a m S p o o n e r ) , a " p o r t manteau" word ( c o i n e d by Lewis C a r r o l l ) or a " s l i p o f the tongue" and can b e s t be d e f i n e d as "an u n i n t e n t i o n a l t i c innovation"  (Sturtevant,, 1947, p. 38).  linguis-  Speech e r r o r s are  c o n s t r a i n e d by the grammar and phonology of a g i v e n language, and because o f t h e s e c o n s t r a i n t s they are t o a c e r t a i n degree p r e d i c t a b l e and non-random ( F r o m k i n , 1973, p. 113). Authors such as Shakespeare, R a b e l a i s  and Lewis  Carroll  used speech e r r o r s i n t h e i r works t o a c h i e v e humourous ends. Freud b e l i e v e d t h a t these d i s t u r b a n c e s o f speech were "the r e s u l t o f c o m p l i c a t e d p s y c h i c a l i n f l u e n c e s , o f elements o u t s i d e the same word, sentence or sequence o f spoken ( F r e u d , 1924; c i t e d i n F r o m k i n , 1973, p. 110).  Speech  words" errors  have a l s o been s t u d i e d i n the hope t h a t such would p r o v i d e i n s i g h t i n t o h i s t o r i c a l l i n g u i s t i c change ( S t u r t e v a n t ,  1947),  i n attempts t o u n d e r s t a n d the speech p r o d u c t i o n p r o c e s s more fully  (Boomer 5 L a v e r , 1968; F r o m k i n , 1968, 1971; Nooteboom,  1969) , and t o i n v e s t i g a t e the p o s s i b l e bases f o r c e r t a i n phonological  u n i t s and r u l e s ( F r o m k i n , 1968,  1  1971).  2  Few i n v e s t i g a t o r s have s p e c u l a t e d as t o the u n d e r l y i n g cause o f speech e r r o r s , a l t h o u g h M e r i n g e r (1908) t r i e d -and f a i l e d -- t o c o r r e l a t e e r r o r p r o d u c t i o n w i t h numerous v a r i a b l e s , such as r a t e o f speech and time o f day.  While  speech e r r o r s have been used as a v e h i c l e f o r i n v e s t i g a t i n g v a r i o u s speech p r o c e s s e s , t h i s temporary "breakdown and r e c a l i b r a t i o n " p r o c e s s i n w h i c h the system i s i n v o l v e d can be s t u d i e d i n i t s own  right; i.e.,  an e x a m i n a t i o n o f the i n -  t r i n s i c s t r u c t u r e of speech e r r o r s i s l o g i c a l l y p r i o r t o t h e i r use f o r o t h e r p u r p o s e s . The m e t h o d o l o g i e s employed  t o c o l l e c t speech e r r o r d a t a ,  as w e l l as the subsequent c l a s s i f i c a t i o n s of such d a t a , have been many and d i v e r s e .  The speech e r r o r s c o l l e c t e d i n the  p r e s e n t s t u d y , f o r example, c o u l d be c l a s s i f i e d and accounted for  almost e n t i r e l y by the d e s c r i p t i o n s p r o v i d e d i n F a i r b a n k s  and Guttman (1958) ; w i t h r e g a r d s p e c i f i c a l l y t o the " r e p e t i t i o n e r r o r s " found i n the p r e s e n t s t u d y , r e s e a r c h e r s i n the f i e l d of d e l a y e d a u d i t o r y feedback (DAF) have e n c o u n t e r e d a s i m i l a r phenomenon which they have l a b e l l e d stutter"  ( c f . Lee, 1951).  In the DAF  "artificial  l i t e r a t u r e , i t has  been n o t e d t h a t s u b j e c t s r e q u i r e a " t u r n around t i m e " ( i . e . , a d e l a y i n which a s u b j e c t can produce a r e p e t i t i o n a f t e r a f i r s t p r o d u c t i o n ) , and t h i s d e l a y time c o u l d have a neurop h y s i o l o g i c a l b a s i s , such as t h a t proposed by Kent and M o l l (1975).  3  An e x a m i n a t i o n o f t h e l i t e r a t u r e p e r t a i n i n g t o funct i o n a l neuroanatomy and the n e u r o p h y s i o l o g y o f motor r e s ponses  ( e . g . , Bowman, 1971; Abbs, 1973) s u g g e s t s t h a t t h i s  d e l a y a r i s e s as a r e s u l t o f c o r t i c a l l y c o n t r o l l e d motor mechanisms (gamma and a l p h a motor s y s t e m s ) ; i . e . , d e l a y time might be a c c o u n t e d f o r by means o f a gamma " d e l a y " loop f o r feedback from t h e p o s i t i o n and movement o f the a r t i c u l a t o r s (tongue, j a w , e t c . ) d u r i n g speech. 1.1  Review o f the L i t e r a t u r e - I n t r o d u c t i o n The l i t e r a t u r e r e l e v a n t t o t h i s s t u d y w i l l be d i s c u s s e d .  in four s e c t i o n s :  (1) a-.i o u t l i n e o f the f u n c t i o n a l neuro-  anatomy o f speech, (2) feedback mechanisms, (3) speech and (4) t i m i n g o f speech.  errors,  The f i f t h s e c t i o n w i l l p r o v i d e a  d i s c u s s i o n and summary o f models o f speech p r o d u c t i o n i n an attempt t o s y n t h e s i z e i n f o r m a t i o n from t h e above-mentioned disciplines. 1.2  F u n c t i o n a l Neuroanatomy o f Speech As has o f t e n been n o t e d ( e . g . , M a c N e i l a g e , 1972, pp.  6-7), t h e importance o f p h y s i o l o g i c a l mechanisms f o r speech i s t h e i r i n t e r a c t i o n i n t h e p r o d u c t i o n o f an a c o u s t i c output which has communicative  significance.  In t h i s  section  a b r i e f o v e r v i e w o f some o f t h e main areas o f the b r a i n w i t h s p e c i f i c s i g n i f i c a n c e i n g e n e r a t i n g speech w i l l be d i s c u s s e d , as w e l l as t h e c e n t r a l nervous system, t h e p e r i p h e r a l nervous system and the s e n s o r y and motor t r a c t s , a l l o f which make  4  up the pathways f o r speech. anatomically speaking,  The  discussion w i l l  from the c o r t e x t o the thalamus  on downward t h r o u g h the m i d b r a i n , pons, m e d u l l a , c r a n i a l n e r v e s and s p i n a l 1.21 The  descend, and  cerebellum,  cord.  C e n t r a l Nervous System c e r e b r a l c o r t e x i s to be regarded  manipulator  o f motor neuron impulses  as the supreme  r e s u l t i n g ' i n speech.  This i d e a has been debated f o r s e v e r a l decades, c u l m i n a t i n g w i t h the n o t i o n t h a t the c e n t r a l nervous system (CNS) be regarded  "as  can  a s e r i e s of f u n c t i o n a l a r c s i n which sub-  c o r t i c a l c e n t e r s are i n a r e c i p r o c a l r e l a t i o n s h i p w i t h c a l areas"  (Berry § Eisenson,  § Roberts,  1959,  w i t h one  p. 15).  1956,  p. 45; c f . a l s o P e n f i e l d  These a r c s are c l a i m e d t o i n t e r a c t  a n o t h e r and not e x c l u s i v e l y w i t h the c o r t e x .  view o f the CNS  as an i n p u t - o u t p u t  e v e r , somewhat outmoded: presence o f feedback and  Pribram  r e f l e x arc' i s now, (1971) has  feedforward  functional "Test-Operate-Test-Exit"  howthe  mechanisms o f the  CNS a  servomechanism, which  matches i n p u t a g a i n s t the o u t p u t t a r g e t . i s at work i n the CNS,  This  described  which c o n t r o l r e c e p t o r f u n c t i o n s and has h y p o t h e s i z e d  process:  corti-  Whichever system  the r e s u l t i s a complex i n t e r a c t i v e  speech.  A u d i t o r y p e r c e p t i o n , w h i c h i s used f o r l e a r n i n g and m a i n t a i n i n g speech, i s b e l i e v e d to be found i n the a u d i t o r y r e c e p t i o n area  (Brodmann's A r e a 22).  It is within this  area  5  t h a t an i n d i v i d u a l may p e r c e i v e sounds b u t not decode meaning, t h i s l a t t e r f u n c t i o n b e i n g accomplished n i c k e ' s a r e a (Area  their  i n Wer-  41-42):  " I n t h e a u d i t o s e n s o r y area [Area 22] a u d i t o r y i m p r e s s i o n s reach c o n s c i o u s n e s s as sounds, and t h e i r l o u d n e s s , q u a l i t y and p i t c h can be d i f f e r entiated. The d i r e c t i o n from which the sound comes and i t s c h a r a c t e r , whether r h y t h m i c a l o r a r h y t h m i c a l , are a l s o determined by t h i s p a r t o f the c o r t e x . The s i g n i f i c a n c e and t h e source o f the sound, however, r e q u i r e the a d j o i n i n g a u d i t o p s y c h i c a r e a f o r t h e i r e l u c i d a t i o n .... I n t h i s a r e a [Areas 41-42] a u d i t o r y i m p r e s s i o n s r e c e i v e t h e i r i n t e r p r e t a t i o n and can be d i f f e r e n t i a t e d from one a n o t h e r , as r e g a r d s t h e i r p r o b a b l e source and o r i g i n , by a s s o c i a t i o n w i t h p a s t e x p e r i e n c e . " ( J o h n s t o n £ W h i l l i s , 1954, p. 1037) I t has been demonstrated  i n recent years that loudness, q u a l -  i t y and p i t c h can a l s o be d i f f e r e n t i a t e d In the p a r i e t a l lobe are Areas  sub-cortically.  1-3 which make p o s s i b l e  awareness o f t o u c h , p r e s s u r e , temperature  and muscle movement.  An awareness o f tongue movements i n a r t i c u l a t i o n may be proj e c t e d from here to speech areas and "may be one o f the c h i e f s t i m u l i i n p r o v o k i n g o r c o n t i n u i n g speech" 1956,  (Berry § Eisenson,  p. 56). The motor p r o j e c t i o n a r e a f o r v o l u n t a r y movement (Area 4)  has a l a r g e p e r c e n t a g e  devoted  t o phonatory  and a r t i c u l a t o r y  movement which sends impulses v i a t h i s p y r a m i d a l t r a c t t o t h e  6  muscles o f the jaw, l i p s , tongue, l a r y n x and pharynx. A r e a 6, the e x t r a p y r a m i d a l a r e a , produces r e f i n e m e n t i n motor b e h a v i o u r such as the s e q u e n c i n g o f v o c a l f o l d adduct i o n , resonance and a r t i c u l a t i o n , or the q u a l i t i e s of i n t o n a t i o n and  rhythm.  A r e a 44, Broca's a r e a , i s where f i b r e s from o t h e r areas concerned w i t h the speech p r o c e s s synapse and then p r o c e e d to the motor p r o j e c t i o n areas f o r the muscles o f speech. Other areas w h i c h may be s i m i l a r i n f u n c t i o n to A r e a 44 are Areas 7A, 7B and 7C, the l a s t o f which i s concerned w i t h the thalamus and w i t h i n t e g r a t i o n o f e m o t i o n a l e x p r e s s i o n i n t o speech. Areas 8-11,  the f r o n t a l i d e a t i o n a l a s s o c i a t i o n a r e a s ,  are c a l l e d upon to i n t e g r a t e p a s t e x p e r i e n c e , , a b s t r a c t t h i n k i n g , r e a s o n i n g and i d e a s i n t o speech. The s t r i a t e b o d i e s , c o m p r i s e d o f the c a u d a t e , l e n t i c u l a r and amygdaloid n u c l e i , t o g e t h e r w i t h the c o r t e x and the thalamus, p r o b a b l y a c t as one u n i t o r a r c ( c f . P e n f i e l d § Rasmussen, 1950, pp. 106-107).  The caudate and  lenticular  n u c l e i b e l o n g to the e x t r a p y r a m i d a l system, and t h e i r axons run to motor n u c l e i o f the b r a i n stem concerned w i t h i n n e r v a t i o n o f the muscles o f the tongue, f a c e , l a r y n x and pharynx. The h i g h e s t i n t e g r a t i v e mechanism f o r speech may, P e n f i e l d and Rasmussen (1950, p. 219) s u g g e s t , "be  as  situated  7 i n some c e r e b r a l a r e a , such as t h e thalamus, and not i n either cerebral cortex".  A l l sensory  t r a c t s have a r e l a y  s t a t i o n i n the thalamus.  Sensory-emotional  r e s p o n s e s , the  q u a l i t y o f t h e v o i c e , f a c i a l e x p r e s s i o n and s u b t l e body g e s t u r e s , as w e l l as c o n c e p t u a l p a t t e r n s o f form, s i z e , q u a l i t y , i n t e n s i t y and t e x t u r e , a r e o r g a n i z e d here f o r t r a n s m i s s i o n to t h e c o r t e x . The  midbrain  c o n t a i n s t h e s u b s t a n t i a n i g r a and r e d  n u c l e i , which a r e p a r t o f t h e e x t r a p y r a m i d a l system, and t h e c e r e b r a l p e d u n c l e s , w h i c h c o n t a i n the p y r a m i d a l pyramidal  tracts.  The  t r a c t i s made up o f t h e c o r t i c o s p i n a l f i b r e s which  run from t h e motor c o r t e x t o the s p i n a l c o r d .  T h i s t r a c t has  c o n t r o l over t h e speech muscles o f the head and neck c r a n i a l n e r v e s V, V I I , I X , X and X I I .  through  The e x t r a p y r a m i d a l  system i s c h i e f l y made up o f t h e s t r u c t u r e s o t h e r than the c o r t e x which send impulses  to the s p i n a l cord, i . e . , s t r i a t e  bodies, cerebellum, red nucleus, substantia n i g r a , e t c . ( c f . N e t t e r , 1974).  The s u b s t a n t i a n i g r a and t h e r e d n u c l e i  have two-way c o n n e c t i o n s  w i t h t h e s t r i a t e b o d i e s , thalamus  and premotor area o f the c o r t e x .  The s u b s t a n t i a n i g r a i s  b e l i e v e d t o c o n t r o l t h e muscles o f f a c i a l e x p r e s s i o n , and the r e d n u c l e i i n a s s o c i a t i o n w i t h the c e r e b e l l u m  c o n t r o l the  g r a d a t i o n and t i m i n g o f m u s c u l a r c o n t r a c t i o n . The  pons, l o c a t e d j u s t below the m i d b r a i n , c o n t a i n s  s o r y and motor pathways, as w e l l as t h e r e t i c u l a r  sen-  formation,  8  which i s l i n k e d w i t h the c e r e b e l l u m and s t r i a t e b o d i e s , making up p a r t o f the e x t r a p y r a m i d a l system.  The  pneumotaxic  c e n t r e o f the pons i s c o n n e c t e d to the hypothalamus  and s t i m -  u l a t e s e x h a l a t i o n and m a i n t a i n s r e s p i r a t o r y rhythm f o r speech. The t r i g e m i n a l s e n s o r y complex c l e u s o f the t r i g e m i n a l  i s the p r i n c i p l e s e n s o r y nu-  (Vth) nerve i n the pons.  The motor  n u c l e i o f the f a c i a l and t r i g e m i n a l nerves i n the pons i n n e r vate v o l u n t a r y f a c i a l speech m u s c u l a t u r e and muscles o f m a s t i cation,  respectively.  The m e d u l l a c o n t a i n s the c e n t r e s which c o n t r o l the r e s p i r a t o r y and c i r c u l a t o r y systems and a l s o r e g u l a t e r a t e and rhythm o f b r e a t h i n g f o r speech.  These c e n t r e s respond t o  incoming s e n s o r y i m p u l s e s from the diaphragm and from the a o r t i c and c a r o t i d c a p i l l a r i e s .  The lower motor neurons o f  the m e d u l l a i n n e r v a t e muscles of the mouth, pharynx  and  l a r y n x f o r speech p r o d u c t i o n v i a s p e c i f i c c r a n i a l nerves (to be d i s c u s s e d b e l o w ) .  The m e d u l l a c o n t a i n s the n u c l e u s s o l i -  t a r i u s which r e c e i v e s a f f e r e n t  ( s e n s o r y ) f i b r e s from the f a -  c i a l , vagus, and g l o s s o p h a r y n g e a l n e r v e s .  The h y p o g l o s s a l  n u c l e u s o f the m e d u l l a s u p p l i e s i n n e r v a t i o n t o tongue muscles. The n u c l e u s ambiguus sends f i b r e s through the g l o s s o p h a r y n g e a l , vagus, and s p i n a l a c c e s s o r y nerves to s u p p l y muscles o f the pharynx and The  larynx.  c e r e b e l l u m , p a r t o f the e x t r a p y r a m i d a l system, i s --  i n a d d i t i o n to p r o v i d i n g f o r f i n e motor c o o r d i n a t i o n i n g e n e r a l -- o f importance i n speech p r o d u c t i o n , by e l a b o r a t e l y  9  controlling  v o l u n t a r y muscle movements, e.g., i n the modula-  t i o n o f p h o n a t i o n and a r t i c u l a t i o n . The  spinal  c o r d conducts s e n s o r y impulses to h i g h e r  c e n t r e s , such as the c e r e b e l l u m  and the thalamus.  mediates c o n t r o l o f motor a c t i v i t i e s  I t also  o f the body below the  face and neck ( e . g . , p o s t u r e , movements and g e s t u r e ) . spinal  The  c o r d a c t s as an i n t e g r a t i n g c e n t r e f o r many r e f l e x  patterns. 1.22 The  P e r i p h e r a l Nervous System c r a n i a l nerves d i r e c t l y a s s o c i a t e d w i t h speech  mechanisms are the t r i g e m i n a l ( V ) , f a c i a l pharyngeal  ( I X ) , vagus ( X ) , a c c e s s o r y  (VII),  glosso-  (XI) and h y p o g l o s s a l  (XII). The  t r i g e m i n a l nerve  motor f i b r e s i m p o r t a n t  ( V ) , c o n t a i n i n g both s e n s o r y and  t o the a r t i c u l a t o r y movements o f  speech, t r a n s m i t s s e n s a t i o n s  o f movement from the muscles o f  m a s t i c a t i o n o f the jaw, sensations  o f t o u c h , temperature and  p a i n from the f a c e , and v o l u n t a r y motor impulses t o t h e jaw.' The  f a c i a l nerve ( V I I ) , as w e l l as c r a n i a l nerves I X - X I I ,  has motor f i b r e s mechanisms..  i n n e r v a t i n g the muscles o f speech  production  The f a c i a l nerve i t s e l f s u p p l i e s the s t r i a t e d  muscles o f the f a c e , the s t y l o h y o i d muscle and t h e s t a p e d i u s muscles.  10  The g l o s s o p h a r y n g e a l nerve (IX) i n n e r v a t e s the s t y l o pharyngeus  muscle, which aids i n v e l a r c l o s u r e .  It likewise  mediates p r o p r i o c e p t i o n o f the p o s t e r i o r t h i r d o f the tongue. The vagus nerve ( X ) , i n c o n j u n c t i o n w i t h c r a n i a l nerves IX and X I , i n n e r v a t e s the v o l u n t a r y muscles o f the pharynx and l a r y n x i n v o l v e d i n speech.  Sensory i m p u l s e s , t r a n s m i t t i n g  p r o p r i o c e p t i v e i n f o r m a t i o n t o the m e d u l l a , c e r e b e l l u m and o t h e r p a r t s o f the e x t r a p y r a m i d a l t r a c t , can e f f e c t f i n e coo r d i n a t i o n , graded c o n t r a c t i o n and t o n i c c o n t r o l n e c e s s a r y f o r speech. The s p i n a l a c c e s s o r y nerve (XI) a s s i s t s the vagus i n motor c o n t r o l o f the pharynx and l a r y n x and i n n e r v a t e s the t r a p e z i u s and s t e r n o m a s t o i d muscles n e c e s s a r y f o r speech breathing. C r a n i a l nerve X I I , the h y p o g l o s s a l , i n n e r v a t e s the a t e d muscles o f the tongue.  stri-  These muscles concerned w i t h  v o l u n t a r y movements of the tongue are the g e n i o g l o s s u s , g e n i o h y o i d , h y o g l o s s u s , s t y l o h y o i d , s t y l o g l o s s u s , and p a l a t o g l o s sus . There are t h i r t y - o n e p a i r s o f s p i n a l n e r v e s , which t r a n s m i t b o t h s e n s o r y and motor i n f o r m a t i o n .  The most impor-  t a n t r o l e o f t h e s e nerves i n speech p r o d u c t i o n c o n s i s t s o f s e n d i n g motor ( e f f e r e n t ) i m p u l s e s t o a c t i v a t e the muscles o f b r e a t h i n g f o r speech.  11  1.23  Sensory T r a c t s  I t i s o f i m p o r t a n c e to t h i s d i s c u s s i o n to remember t h a t proprioception  (muscle p o s i t i o n , t e n s i o n and movement) i s  r e s p o n s i b l e f o r the r a t e , f o r c e , d i r e c t i o n and e x t e n t v o l u n t a r y movements.  One  of  of the l a r g e s t systems o f sensory  t r a c t s t r a n s m i t t i n g such i n f o r m a t i o n c o n s i s t s o f the v e n t r a l and  l a t e r a l spinothalamic  tracts.  As an example o f r e l a y s along utilize  the a u d i t o r y pathway.  The  a sensory t r a c t , we stimulus  is  will  transformed  i n t o an e l e c t r o c h e m i c a l i m p u l s e i n the c o c h l e a , and the  first  synapse i s l o c a t e d i n the c o c h l e a r n u c l e u s of the m e d u l l a . The  f i b r e t r a c t ascends i n the l a t e r a l l e m n i s c u s t h r o u g h the  pons to the m i d b r a i n . i o r c o l l i c u l u s and  There i s another synapse i n the  a f i n a l one  infer-  i n the m e d i a l g e n i c u l a t e body  o f the t h a l a m u s , from which the i n f o r m a t i o n then passes t o the a u d i t o r y r e c e p t i o n a r e a the  (Area 22)  and  to o t h e r areas i n  cortex. W h i l e the a u d i t o r y i m p u l s e i s b e i n g  oceptive  i m p u l s e s from muscles i n the tongue, l i p s and  (among o t h e r s )  are r e p o r t i n g s h i f t s i n p o s i t i o n and  which w i l l be used i n the p r o d u c t i o n Eisenson,  transmitted, proprijaw  tension  of speech ( c f . Berry  §  1956).  I t i s w o r t h n o t i n g here the d i f f e r e n c e s between e f f e r e n t and  afferent tracts.  An a f f e r e n t , or s e n s o r y ,  an impulse from the p e r i p h e r y  tract  conducts  towards the c o r t e x , w h i l e  an  12  e f f e r e n t , o r motor, t r a c t conducts impulses from t h e CNS t o e f f e r e n t nerve endings i n m u s c l e s . 1.24  Motor Systems  Two t r a c t s c o m p r i s i n g t h e p y r a m i d a l system, the c o r t i c o s p i n a l and c o r t i c o b u l b a r t r a c t s , o r i g i n a t e i n the motor and premotor areas o f the c o r t e x . The c o r t i c o b u l b a r t r a c t i s i m p o r t a n t f o r speech p r o d u c t i o n , s i n c e i t a c t i v a t e s the muscles o f the tongue,  lips,  jaw, pharynx and l a r y n x . The c o r t i c o s p i n a l t r a c t , h a v i n g c e l l b o d i e s i n t h e p r e c e n t r a l gyrus ( i . e . , i n t h e f r o n t a l l o b e ) o f the c o r t e x , makes i t s way v i a the i n t e r n a l c a p s u l e (a f i b r e t r a c t ) t o the c e r e b r a l peduncles ( i . e . , a c r o s s i n g o f s e v e r a l f i b r e t r a c t s ) i n the m i d b r a i n .  This f i b r e t r a c t decussates, or crosses, i n  the m e d u l l a and then passes i n t o the s p i n a l c o r d , s y n a p s i n g w i t h motor c e l l s e f f e c t i n g v o l u n t a r y muscle c o n t r a c t i o n .  The  c o r t i c o b u l b a r t r a c t f o l l o w s the same r o u t e u n t i l i t passes i n t o t h e pons and m e d u l l a , s y n a p s i n g w i t h lower motor neurons o f c r a n i a l n e r v e s V and V I I - X I I .  From here f i b r e s o f t h i s  t r a c t c o n t i n u e on t o i n n e r v a t e the muscles o f speech. The e x t r a p y r a m i d a l system i s a l s o v i t a l t o the f i n e l y c o o r d i n a t e d motor a c t i v i t y n e c e s s a r y f o r speech.  I t s organi-  z a t i o n i s d e s c r i b e d by G r i n k e r and Bucy (1949, p. 274) as follows:  13  " A l l o f t h e s e s u b c o r t i c a l s t r u c t u r e s w h i c h are r e c i p i e n t s . o f i m p u l s e s from the p r e c e n t r a l c o r tex have two p r i n c i p a l p r o j e c t i o n systems. 1) They p r o j e c t to the l a t e r a l n u c l e u s of the thalamus and thence back t o the p r e c e n t r a l r e g i o n ( c o r t e x ) and 2) they have a d e s c e n d i n g pathway down the s p i n a l c o r d to the a n t e r i o r horn c e l l s . ... [The n e c e s s i t y of t h i s system f o r speech a c t i v i t i e s i s t h a t i t ] c o n t r o l s ' , a c t i v a t e s , and i n h i b i t s the a s s o c i a t e d musculat u r e o r p r o t a g o n i s t i c muscles which must be approp r i a t e l y contracted. ... I t c o n t r o l s the r e f l e x i n n e r v a t i o n of the s k e l e t a l muscles t o produce what i s commonly known as t o n e . " [ C i t e d i n Berry § E i s e n s o n , 1956, p. 71] As can be deduced from the above d i s c u s s i o n o f neuroanatomical structures  and t h e i r f u n c t i o n s , speech can be r e -  garded as a v e r y complex i n t e g r a t i v e p r o c e s s , encompassing not o n l y motor systems f o r i t s p r o d u c t i o n ,  but a l s o s e n s o r y  m o n i t o r i n g s y s t e m s , w h i c h are to be d i s c u s s e d  i n more d e t a i l  i n the f o l l o w i n g s e c t i o n . 1.3  Feedback 1.30  Mechanisms  Introduction  The goal o f t h i s s e c t i o n i s an a p p r e c i a t i o n physiological basis  for peripheral  feedback systems i n o p e r a t i o n  during  o f the neuro-  proprioceptive/kinesthetic the speech a c t .  The p r e -  s e n t a t i o n here i s germane t o the d i s c u s s i o n of models o f speech production  i n Section  1.6.  R e s e a r c h e r s , such as Abbs (1973),  14  Hardy  (1970) and Bowman (1971; c f . Smith's 1973 r e v i e w o f  Bowman), have c o n t r i b u t e d most o f t h e i n f o r m a t i o n in this section.  discussed  The a u d i t o r y system as a feedback mechan-  ism f o r speech i s a l s o d i s c u s s e d h e r e , and t h e main body o f t h i s s e c t i o n ' s p r e s e n t a t i o n comprises an i n t r o d u c t i o n t o t h e gamma, o r s p i n d l e , motor system and i t s import f o r feedback. 1.31  The Gamma/Spindle Motor  System  "The gamma-loop can be c o n s i d e r e d as t h e gamma e f f e r e n t f i b e r s , t h e s p i n d l e f i b e r c o n t r o l l e d by the e f f e r e n t f i b e r s , and t h e s y n a p t i c c o n n e c t i o n s made by the s p i n d l e a f f e r e n t w i t h a l p h a motoneurons ( a f t e r S m i t h , 1969)." (Abbs, 1973, p. 176) A muscle s p i n d l e i s a s m a l l c y l i n d r i c a l body t o t h e main body o f t h e muscle. muscle f i b r e s .  I t contains  i n t r a f u s a l and e x t r a f u s a l  The motor i n n e r v a t i o n o f t h e body o f a muscle  i s c a r r i e d o u t by a l p h a motoneurons i n t h e c o r t e x , w h i l e i n n e r v a t i o n o f muscle neurons.  s p i n d l e s i s c a r r i e d o u t by gamma moto-  Sensory neurons  synaptic reflex  a r c w i t h alpha  It i s instructive Smith's  i n t h e muscle s p i n d l e form a monomotoneurons.  at t h i s p o i n t t o c i t e d i r e c t l y from  (1973) summary o f t h e major p o i n t s i n Bowman's  (1971)  work c o n c e r n i n g the gamma motor system: "Most m u s c l e s , i n c l u d i n g many b u t n o t a l l o f t h e muscles i n n e r v a t e d by t h e c r a n i a l n e r v e s , c o n t a i n s m a l l f u s i f o r m r e c e p t o r s known as muscle s p i n d l e s . The s p i n d l e s are l o c a t e d m e c h a n i c a l l y i n p a r a l l e l w i t h t h e muscle f i b e r s , which are c a l l e d e x t r a f u s a l  15  f i b e r s i n t h i s context. The s p i n d l e sends i n f o r m a t i o n back t o t h e c e n t r a l nervous system (CNS) over two types o f f i b e r s : large diameter group l a f i b e r s , and somewhat s m a l l e r group I I fibers. The a f f e r e n t i n f o r m a t i o n , which can a r i s e f o r example when t h e s p i n d l e i s s t r e t c h e d , i n d i c a t e s i n a r e l a t i v e sense both t h e l e n g t h of t h e muscle (group l a and group I I f i b e r s ) and t h e r a t e o f change o f muscle l e n g t h (group l a f i b e r s o n l y ) . E x t r a f u s a l muscle f i b e r s r e c e i v e t h e i r motor i n n e r v a t i o n from l a r g e d i a meter a l p h a f i b e r s , which are axons o f a l p h a motoneurones i n t h e s p i n a l c o r d o r b r a i n s t e m motor n u c l e u s . S p i n d l e s a l s o c o n t a i n muscle (contractile) fibers, called intrafusal fibers. They r e c e i v e t h e i r i n n e r v a t i o n from gamma f i b e r s (axons o f gamma motoneurones). The gamma i n n e r v a t i o n o f t h e s p i n d l e i s a complex i s s u e , and i s n o t a t p r e s e n t c o m p l e t e l y u n d e r s t o o d . The a l p h a and gamma motor systems i n mammals are a n a t o m i c a l l y and f u n c t i o n a l l y d i s t i n c t . The s p i n d l e . w i t h i t s a s s o c i a t e d a f f e r e n t and motor nerve s u p p l i e s i s c o n s i d e r e d t o be one o f the most i m p o r t a n t mechanisms r e g u l a t i n g t h e s t a b i l i t y and a c c u r a c y o f muscle c o n t r a c t i o n . An a c c u r a t e u n d e r s t a n d i n g o f the f u n c t i o n i n g o f t h i s system i s thus o b v i o u s l y i m p o r t a n t f o r d e t a i l e d neurom u s c u l a r s t u d i e s o f the speech p r o d u c t i o n apparatus." (Smith, 1973, p. 172) Of s i m i l a r import i s the work o f Merton (1953; c i t e d by Abbs, 1973), who c l a i m s  t h a t t h e s p i n d l e motor system can pro-  duce o u t p u t p r o p o r t i o n a l t o t h e l e n g t h e r r o r between e x t r a f u s a l and i n t r a f u s a l f i b r e systems.  The e r r o r s i g n a l i s  16  t r a n s m i t t e d t o the motoneurons of the e x t r a f u s a l f i b r e s "negative  feedback".  The  muscle l e n g t h i s then  as  indirectly  c o n t r o l l e d by c o n t r a c t i o n o f the s p i n d l e f i b r e s .  Abbs (1973)  goes on to note t h a t a common m i s u n d e r s t a n d i n g of the  spindle  motor system f o r feedback i n speech i s t h a t many i n v e s t i g a t o r s f e e l i t to be  a p e r i p h e r a l neuromotor network.  In support o f  t h i s c o n t e n t i o n , Abbs c i t e s Mortimer and A k e r t ' s i n g s from r e s e a r c h w i t h p r i m a t e s which c o n f i r m s motoneurons have d i s c r e t e areas of c o r t i c a l  t h a t "gamma  representation  very s i m i l a r t o those o f a l p h a motoneurons and the two  (1961) f i n d -  i n some cases  types are e x c i t e d by the same c o r t i c a l r e g i o n .  r e p r e s e n t a t i o n suggests-,  not  Such  a d i f f u s e f a c i l i t o r y a c t i o n from  the s p i n d l e motor system, but a d e t a i l e d c o r t i c a l l y c o n t r o l l e d function"  (Abbs, 1973,  p.  178).  I t i s perhaps the r o l e o f the c e r e b e l l u m , a f f e r e n t muscle i m p u l s e s from the b r a i n s t e m coordinate  motor and s e n s o r y a c t i v i t y  c i t e d i n Abbs, 1973, the c e r e b e l l u m  p. 178).  which r e c e i v e s  and c o r t e x , t o  ( c f . Ruch et a l . , 1967;  From p a t h o l o g i c a l c o n d i t i o n s  of  i t has been n o t e d to c o n t r o l p r e c i s i o n o f r a t e ,  range, f o r c e and  d i r e c t i o n o f v o l u n t a r y motion.  In sura: "the s p i n d l e motor system i s - n o t s i m p l y a p e r i p h e r a l c o n t r o l mechanism t h a t serves o n l y to modulate more central activities. The [ a v a i l a b l e ] data ... would suggest t h a t t h i s system has the f u n c t i o n a l r e p r e s e n t a t i o n to i n t e r a c t w i t h alpha motoneuron systems i n the c o r t i c a l and s u b c o r t i c a l g e n e r a t i o n of speech movements. Indeed, G r a n i t , as e a r l y as 1955 , suggested e x i s t e n c e o f s e p a r a t e but i n t e r a c t i n g c o n t r o l  17  of gamma and a l p h a motoneurons a t h i g h e r neuromotor centers." (Abbs, 1973, p. 178) Abbs mentioned t h e h e s i t a t i o n o f many s p e e c h - p r o d u c t i o n researchers  t o a s s i g n t h e r o l e o f " d e t e c t i o n and c o r r e c t i o n "  o f speech e r r o r s t o t h e gamma-loop because o f the r e l a t i v e l y l o n g d e l a y time i n v o l v e d .  The c o n t r i b u t i o n o f p r i m a r y s p i n d l e  a f f e r e n t f i b r e s and the s p e c i f i c r o l e o f the s p i n d l e . m o t o r system i n movement c o n t r o l are c o n s i d e r e d .  As mentioned above,  group l a a f f e r e n t s p i n d l e s r e l a y i n f o r m a t i o n on r a t e o f l e n g t h change o f t h e m u s c l e , and thus l e n g t h can be a n t i c i p a t e d and problems o f o v e r s h o o t o r o s c i l l a t i o n avoided.  Consideration  o f t h e r o l e o f these group l a f i b r e s , e s p e c i a l l y t h a t o f feedback d e l a y , l e a d s t o an awareness o f a s e r v o f u n c t i o n f o r t h e gamma e f f e r e n t system ( c f . Abbs, 1973, p. 179). I n t h i s r e gard F a i r b a n k s  (1954) p o s t u l a t e d a model f o r speech i n terms  o f a s e r v o s y s t e m (see a l s o S e c t i o n 1.6 b e l o w ) ; such a model compares o u t p u t t o i n p u t and a d j u s t s i n p u t a c c o r d i n g l y i n t h i s closed-loop 1973,  system.  p. 179) s u p p o r t s  Von E u l e r (1966; c i t e d i n Abbs,  t h e n o t i o n o f a s e r v o s y s t e m w i t h work  on muscle s p i n d l e s i n the i n t e r c o s t a l muscles o f the c h e s t , i n which f i r i n g r a t e o f a l p h a motoneurons i n c r e a s e s increased rate of r e s p i r a t i o n .  with  Thus,  "A c o n t i n u o u s e r r o r s i g n a l t h a t modulates c e n t r a l l y generated alpha a c t i v i t y could provide a b a s i s f o r the continuous c o r r e c t i o n o f intended muscle l e n g t h as s e t by t h e i n d e p e n d e n t l y a c t i v a t e d gamma motor f i b e r s . " (Abbs, 1973, p. 179)  18  In s p i t e o f i t s p r e d i c t i v e powers, a s i m p l e servo model cannot e x p l a i n c o n t i n u o u s c o n t r o l i n p r o d u c t i o n o f s h o r t r a p i d muscle speech.  movements, such as those n e c e s s a r y f o r  The d e l a y " l o o p " i n humans i s around 20-80 ms  ( c f . Campbell, 1968; A l s t o n e t a l . , 1967; Sears § Newsome D a v i s , 1968:  a l l c i t e d i n Abbs, 1973, p. 1 7 9 ) , and some  speech movements are completed i n l e s s t i m e , such as those i n v o l v i n g tongue t i p , w h i c h are o f t e n i n i t i a t e d and completed i n l e s s than 50 ms. Stark  (1968; c i t e d i n Abbs, 1973, p. 180) has s u g g e s t e d  t h a t the s p i n d l e  (gamma) system i s used when " c o n t i n u o u s " con-  t r o l i s r e q u i r e d , and t h e a l p h a system may o p e r a t e when h i g h speed o r b a l l i s t i c - t y p e movement i s r e q u i r e d . many i n v e s t i g a t o r s  Research by  ( f o r d e t a i l s , see Abbs, 1973, pp. 180-181)  l e d Abbs to summarize the p o s s i b l e r o l e o f t h e s p i n d l e motor system as a " v a r i a b l e " s e r v o model, i n the f o l l o w i n g terms: " t h e s p i n d l e motor system o p e r a t e s (1) when t h e muscle i s d i s t u r b e d i n an i s o m e t r i c s t a t e [ i . e . , when t h e ends o f the muscle are f i x e d i n p l a c e and increase i n tension occurs without appreciable i n creases i n length] or during c o n t r o l l e d i s o t o n i c c o n t r a c t i o n [ i . e . , when the t o t a l muscle i s o f equal t e n s i o n ] by an unexpected f o r c e ( t h a t i s , t h e s p i n d l e system attempts t o m a i n t a i n l e n g t h o r a c e r t a i n r a t e of change i n l e n g t h ) , (2) t o develop speed i n t h e i n i t i a t i o n o f c o n t r a c t i o n , and (3) t o p r o v i d e a n t a g o n i s t i c f a c i l i t a t i o n t o damp movement and p r e v e n t overshoot." (Abbs, 1973, p. 181)  19  1-32 The  A u d i t o r y Feedback f i r s t s u g g e s t i o n t h a t a u d i t o r y feedback may  be i n -  v o l v e d i n speech m o n i t o r i n g and p r o d u c t i o n , i n terms o f the e f f e c t s o f d e l a y e d a u d i t o r y feedback on speech, was by Lee  (1950, 1951)  and B l a c k  (1951).  Other speech p r o d u c t i o n  models employing a u d i t o r y feedback were p r o p o s e d by (1954) and Chase (1958). low i n S e c t i o n Van  T h e i r models w i l l  Fairbanks  be d i s c u s s e d be-  1.6.  R i p e r (1971) s p e c u l a t e s about the r o l e o f a u d i t o r y  feedback f o r speech p r o d u c t i o n . v e r s y between c o n t i n u o u s Van  suggested  Acknowledging the c o n t r o -  and i n t e r m i t t e n t m o n i t o r i n g o f speech,  R i p e r views speech as o p e r a t i n g l i k e a servosystem  under  o r d i n a r y c o n d i t i o n s and c l a i m s t h a t : " I n f o r m a t i o n about the speech o u t p u t i s r e t u r n e d to the c e n t r a l i n t e g r a t i n g mechanism through s i x a u d i t o r y c h a n n e l s , v i a the r i g h t and l e f t feedback r o u t e s from (1) a i r b o r n e s i d e - t o n e , (2) bone-conducted s i d e - t o n e , and (3) t i s s u e connected s i d e - t o n e . Other feedback s i g n a l s come from the k i n e s t h e t i c - t a c t i l e p r o p r i o c e p t i v e s e n s o r s on b o t h s i d e s of the body. S t r o m s t a (1962) showed t h a t a u d i t o r y feedback s i g n a l s i n t h e s e d i f f e r e n t channels a r r i v e at markedly d i f f e r ent times and t h a t the temporal i n f o r m a t i o n - p r o c e s s i n g of speech output by the b r a i n i s very complex. Some c e n t r a l mechanisms f o r i n t e g r a t i n g a l l these feedback s i g n a l s must be p r e s e n t , a l t h o u g h t h e i r n a t u r e i s not y e t known." (Van R i p e r , 1971, p. 383) Hardy (1970) d i s c u s s e d the importance o f a u d i t o r y monit o r i n g f o r maintenance o f speech p r o d u c t i o n .  He  considered  20  the  c o n g e n i t a l l y deaf who  do not u s u a l l y develop  intelligible  speech and the a d v e n t i t i o u s l y deaf ( i . e . , deafened a f t e r l e a r n i n g t o speak) who  show a slow d e t e r i o r a t i o n o f the speech  p r o c e s s ( c f . S a t a l o f f , 1966; c i t e d by Hardy, 1970, p. 50). Hardy s u p p o r t e d the b e l i e f  ( a f t e r Chase, 1958, and o t h e r s )  t h a t the a u d i t o r y s i g n a l i s p a r t o f the t o t a l s e n s o r y experi e n c e used i n g e n e r a t i n g speech w i t h complete i n f o r m a t i o n about speech m u s c u l a t u r e p a t t e r n i n g c o n t a i n e d i n the speech " t a r g e t " . Lombard ( c i t e d i n Hardy, 1970, p. 5 1 ) , who b l o c k e d a u d i t o r y feedback by masking the s u b j e c t s ' speech w i t h h i g h i n t e n s i t y n o i s e , found t h a t -- o t h e r than r a i s i n g the i n t e n s i t y l e v e l o f the v o i c e -- speakers showed l i t t l e culation. of  d i s r u p t i o n of a r t i -  T h i s l e d Hardy t o r e j e c t F a i r b a n k s ' s (1954) model  c l o s e d - l o o p feedback f o r speech, where the system would be  dependent on a u d i t o r y feedback at a l l t i m e s .  Perhaps the  speaker-, i n r a i s i n g h i s v o i c e , i s a d j u s t i n g h i s a u d i t o r y feedback l e v e l so t h a t i t i s a u d i b l e under such c o n d i t i o n s , a t l e a s t v i a bone c o n d u c t i o n .  The a d v e n t i t i o u s l y deafened speaker  does n o t l o s e speech i m m e d i a t e l y , i n s p i t e o f the a u d i t o r y feedback h a v i n g been l o s t .  Hardy's c o n c l u s i o n may  shed some  l i g h t on t h e s e c o n s i d e r a t i o n s : " i t must be c o n c l u d e d t h a t i n t r a o r a l s e n s a t i o n s can p r o v i d e cues f o r p o s i t i o n i n g o f the speech musculat u r e once the a p p r o p r i a t e p a t t e r n i n g has been l e a r n e d , and they can c o n t i n u e to do so i n the absence o f a u d i t o r y feedback." (Hardy, 1970, p. 51)  21  1.33  Summary  To s y n t h e s i z e physiology  i n f o r m a t i o n from S e c t i o n 1.2 on neuro-  and from t h i s s e c t i o n , a s p e c u l a t i v e comment from  Konigsmark (1970) , based on h i s knowledge o f n e u r a l s t r u c t u r e s and t h e i r c o n n e c t i o n s ,  i s appropriate  at t h i s  time:  "The i n t e g r a t i v e a c t i v i t y r e s u l t i n g i n speech p r o b a b l y b e g i n s i n the c e r e b r a l c o r t e x w i t h a concept which can be v o c a l i z e d . Broca's area i n t h e c o r t e x may then be i n f l u e n c e d t o i n i t i a t e the speech p r o c e s s . P r o j e c t i o n s from t h i s c o r t i c a l r e g i o n go to the motor c o r t e x . From here a major p r o j e c t i o n courses t o t h e motor n u c l e i i n v o l v e d i n speech, t h a t i s , t h e h y p o g l o s s a l n u c l e u s , t h e nuc l e u s ambiguus, the f a c i a l n u c l e u s , and the motor n u c l e u s o f t h e V t h n e r v e . At the same t i m e , f i b e r s from the c e r e b r a l c o r t e x p r o j e c t to the b a s a l gangl i a , and to t h e c e r e b e l l a r c o r t e x v i a the p o n t i s [pons]. These p r o j e c t i o n s p r o b a b l y f u n c t i o n to smooth and t o c r e a t e t h e n e c e s s a r y motor tonus f o r vocalization. P r o j e c t i o n s from Broca's area t o the r e s p i r a t o r y motor a r e a may c o o r d i n a t e t h i s a c t i v i t y w i t h speech. "Neurons i n t h e h y p o g l o s s a l n u c l e u s , n u c l e u s ambiguus, f a c i a l n u c l e u s , and motor n u c l e u s o f t h e Vth nerve a r e p l a y e d upon by p r o j e c t i o n s from the p r e c e n t r a l gyrus and by t h e c e r e b e l l a r c o r t e x v i a the r e d n u c l e u s . A l s o , s h o r t e r connections i n t e r connect these n u c l e i w i t h one a n o t h e r , p o s s i b l y aiding i n t h e i r coordinated a c t i v i t y . F i b e r s from these n u c l e i a c t upon the m u s c u l a t u r e o f the tongue, l a r y n x , mouth, and jaw t o produce speech. "Sensory endings i n the mucosa and m u s c u l a t u r e o f t h e tongue, l a r y n x , mouth, and jaw are a c t i v a t e d by t o u c h , p r e s s u r e , and p o s i t i o n . T h i s i n f o r m a t i o n  22  i s f e d i n t o the d o r s a l horns o f the s p i n a l c o r d , the n u c l e u s s o l i t a r i u s , and t o the t r i g e m i n a l s e n s o r y complex. These s t r u c t u r e s are a l s o i n f l u e n c e d by the c e r e b r a l c o r t e x and r e t i c u l a r f o r m a t i o n , p o s s i b l y enhancing or dampening t h e i r a c t i v i t y , as the o c c a s i o n demands. These sens o r y n u c l e i then p r o j e c t to the v e n t r a l p o s t e r i o r m e d i a l n u c l e u s o f the thalamus, and then t o the p o s t c e n t r a l gyrus o f the c o r t e x . " A u d i t o r y feedback o f what i s b e i n g s a i d p r o j e c t s t o the t r a n s v e r s e temporal g y r i . From these g y r i t h e r e are p r o j e c t i o n s t o the motor c o r t e x , a l l o w i n g a comparison o f the r e s u l t s o f speech and p o s s i b l y i n f l u e n c i n g the motor p r o d u c t i o n o f speech." (Konigsmark, 1970, p. 17) 1. 4  Speech E r r o r s As d e f i n e d by Boomer and L a v e r (1968) , a " s l i p o f the  tongue  ... i s an i n v o l u n t a r y d e v i a t i o n i n performance  from  the speaker's c u r r e n t p h o n o l o g i c a l , grammatical or l e x i c a l intention"  ( F r o m k i n , 1971, p. 29).  L i n g u i s t i c a l l y , speech e r r o r s have been s t u d i e d f o r seve r a l reasons:  (1) t o p r o v i d e i m p o r t a n t c l u e s f o r language  change, to p r o v i d e a s o u r c e f o r s t u d y i n g h i s t o r i c a l  linguistic  change, as s u g g e s t e d by Hermann P a u l ( S t u r t e v a n t , 1917; MacKay, 1970);  (2) t o u n d e r s t a n d b e t t e r the speech p r o d u c t i o n p r o c e s s  v i a the mechanisms o f speech 1968; Nooteboom, 1969); and  (Boomer § L a v e r , 1968;  Fromkin,  (3) t o draw a d i s t i n c t i o n between  "competence" and "performance", and to demonstrate of p h o n o l o g i c a l u n i t s and r u l e s  (Fromkin, 1968).  the r e a l i t y  23  Speech e r r o r s can o c c u r whenever speech i s used. M e r i n g e r (1908) r e c o r d e d , a l o n g w i t h t h e speech e r r o r s , t h e speaker's b i r t h d a t e , h i s e d u c a t i o n a l  background, s t a t e o f  h e a l t h , degree o f t i r e d n e s s , r a t e o f speech, and the time o f day at which such e r r o r s o c c u r r e d ,  only to f i n d that  there  was no c o r r e l a t i o n o f any o f these f a c t o r s w i t h the e r r o r s observed. Several  i n v e s t i g a t o r s have devoted time to c l a s s i f y i n g  speech e r r o r s i n t o such c a t e g o r i e s o r replacement o f a u n i t  omission  (Boomer § L a v e r , 1968), o r i n t o phon-  emic yjs non-phonemic e r r o r s considers  as m i s o r d e r i n g ,  (Nooteboom, 1969).  Fromkin (1971)  e r r o r s , n o t f o r purposes o f c l a s s i f i c a t i o n , but as  evidence f o r underlying  u n i t s i n speech, such as s y l l a b l e ,  phoneme and f e a t u r e . From Fromkin's (1968) r e s e a r c h see  on speech e r r o r s , one can  t h a t such e r r o r s obey r u l e s o f the grammar and are not r a n -  domly g e n e r a t e d .  Her r e s u l t s show t h a t :  (1) f e a t u r e s , seg-  ments and s y l l a b l e s make up u n i t s o f p r o d u c t i o n ;  (2) segments  i n a s y l l a b l e are o r d e r e d , and t h i s o r d e r i s not v i o l a t e d i n the p r o d u c t i o n class  o f an e r r o r ; (3) morphemes o r words o f the same  ( i . e . , r o o t s , a f f i x e s , etc.) are u s u a l l y  interchanged  w i t h one a n o t h e r ; (4) i n t o n a t i o n and p r i m a r y word s t r e s s r e main i n the same p o s i t i o n , r e g a r d l e s s p h o l o g i c a l and p h o n e t i c o r p h o n o l o g i c a l  o f the e r r o r ; (5) morc o n s t r a i n t s are p l a c e d  on a word at d i f f e r e n t times i n t h e g e n e r a t i o n  o f an  utterance;  (6) n o n - p e r m i s s i b l e p h o n e t i c sequences ( i . e . , those not chara c t e r i s t i c o f t h e language) do not o c c u r ; (7) semantic .  24  f e a t u r e s may and  be d i s p l a c e d , r e s u l t i n g i n a semantic e r r o r ;  (8) words w i t h s i m i l a r i t y of p h o n o l o g i c a l form are  candidates  likely  f o r s u b s t i t u t i o n as an e r r o r ( c f . F r o m k i n , 1971).  As.Fromkin (19 71) and MacKay (1970) have n o t e d , speech e r r o r s are more l i k e l y s i m i l a r phonetic  to o c c u r between words t h a t c o n t a i n  elements.  I t has  s u l t a n t e r r o r s of metathesis  o f two  a l s o been n o t e d t h a t r e s e q u e n t i a l phonemes i n  words (e . g. , /assk/ -> /aeks/) of t e n seem to i n v o l v e the /s/:  " I n a number of p e r c e p t i o n t e s t s , the h i s s (such  occurs w i t h for  sibilant  [s] i s o f t e n ' m i s p l a c e d ' ;  i.e., i t is difficult  s u b j e c t s to judge where the n o i s e occurs  (Fromkin,  1971,  p.  the data) one may  39).  On  as  i n an  utterance"  the b a s i s of such statements  suggest t h a t words of s i m i l a r  (and  phonological  make-up i n v o l v i n g the s i b i l a n t / s / are the most l i k e l y  to  c r e a t e speech e r r o r s . Of the s t u d i e s c a r r i e d out on speech e r r o r s , those  of  M e r i n g e r and Mayer (1895) and M e r i n g e r (1908) are the most e x t e n s i v e i n terms o f number o f e r r o r s and p o s s i b l e e x t r a linguistic over one  correlations.  Boomer and L a v e r (1968) c o l l e c t e d  hundred e r r o r s , and  Fromkin (1971) r e p o r t e d over s i x  hundred e r r o r s ; but o n l y Boomer and L a v e r t a p e - r e c o r d e d errors.  Fromkin c o l l e c t e d hers  i n an a n e c d o t a l  their  fashion,  g e n e r a l l y w i t h the s p e a k e r r e p o r t i n g a f t e r the f a c t what he had  s a i d and had meant t o say.  One  major problem w i t h From-  k i n ' s method o f d a t a c o l l e c t i o n f o r a d i s c u s s i o n at the molec u l a r l e v e l of speech p r o d u c t i o n  i s that subtle  phonetic  25  d i f f e r e n c e s , o r d e v i a n c i e s , i n an e r r o r w i l l  ( a t l e a s t some-  t i m e s ) be m i s s e d by t h e s p e a k e r and hence n o t r e p o r t e d , l e a d ing  t o f a l s e c l a i m s about the p h o n o l o g i c a l / p h o n e t i c form --  and perhaps cause -- o f a speech In  error.  summary, speech e r r o r s have been used i n v a r i o u s i n -  v e s t i g a t i o n s t o t e s t d i v e r s e h y p o t h e s e s , b u t no e m p i r i c a l exa m i n a t i o n o f the e r r o r phenomena has i t s e l f been conducted. As a r e s u l t o f such c o n s i d e r a t i o n s , i t was f e l t t h a t an exami n a t i o n o f d u r a t i o n s o f segments i n speech e r r o r s ,  specifically  i n w o r d - i n i t i a l consonant c l u s t e r s -- an a s p e c t o f the problem not i n v e s t i g a t e d by M e r i n g e r o r o t h e r s -- would prove i n f o r m a t i v e and h e l p e l a b o r a t e hypotheses c o n c e r n i n g the g e n e s i s o f such e r r o r s . 1.5  Timing o f Speech T i m i n g , f o r the purposes o f t h i s s t u d y , i s d e f i n e d as a  sequential ordering of a r t i c u l a t o r y events, t h e o r e t i c a l l y based on n e u r o m u s c u l a r i m p u l s e s sent by the b r a i n t o the a r t i c u l a t o r s and programmed i n some h y p o t h e t i c a l u n i t , such as a phoneme, morpheme, o r s y l l a b l e . I t i s n o t known from the l i t e r a t u r e whether t i m i n g o f speech i s r e g u l a r ; i . e . ,  whether  i t remains c o n s t a n t , f o r ex-  ample, from s t r e s s t o s t r e s s w i t h i n an u t t e r a n c e ( c f . O h a l a , 1970).  Nor i s i t known when t i m i n g b e g i n s ; i . e . ,  whether a  t i m i n g programme i s s e t down when the f i r s t phoneme i s u t t e r e d  26  or as soon as the i m p u l s e i s i n i t i a t e d i n the b r a i n .  Ohala  (1973) g i v e s r e s u l t s which s u p p o r t the c l a i m s t h a t t h e r e i s no u n d e r l y i n g speech rhythm o r time programme, as c l a i m e d K o z h e v n i k o v and C h i s t o v i c h  by  (1965).  A number o f i n v e s t i g a t o r s have c o n s i d e r e d t i m i n g i n a t tempts to c o n s t r u c t models  o f speech p r o d u c t i o n ,  together  w i t h c o n c o m i t a n t c o a r t i c u l a t o r y e f f e c t s ( e . g . , Haggard, Kent $ M o l l , 1975 ; L e h i s t e , 1971; O h a l a , 1970 , 1973). models  can u s u a l l y be c l a s s i f i e d  do o r do n o t employ duction  1973; These  i n terms o f systems which  c o n s i d e r a t i o n s o f feedback i n speech p r o -  (see a l s o S e c t i o n 1.6).  Timing i s considered  i n t h i s study o n l y i n s o f a r as i t i s  a p o s s i b l e d e t e r m i n a n t o f the d u r a t i o n o f segments w h i c h , i t is t e n t a t i v e l y hypothesized 1.6  Models o f Speech 1.60  here, i t constrains.  Production  Introduction  Research on speech e r r o r s , t i m i n g o f speech and feedback has l e d to the f o r m u l a t i o n o f numerous t h e o r i e s and models speech p r o d u c t i o n , s e v e r a l o f w h i c h were b r i e f l y earlier. classified  In g e n e r a l , models  o f speech p r o d u c t i o n  of  mentioned can be  as e i t h e r " c l o s e d - l o o p " or "open-loop": the former  r e f e r s t o a system which -- i t i s s p e c u l a t e d  -- employs  feed-  back t o r e g u l a t e and a d j u s t s p e e c h , the l a t t e r t o a system which does n o t .  The c l o s e d - vs open-loop d i s t i n c t i o n has been  27  v a r i o u s l y designated  as a " c h a i n " vs_ "comb" model  (Bernstein,  1967), " s e q u e n t i a l c h a i n " vs_ " p l a n " model (Lenneberg, 1967), "hypothesis  1" vs_ " h y p o t h e s i s  2", u s i n g e f f e r e n t and a f f e r e n t  impulses (Kozhevnikov § C h i s t o v i c h , 1965) , and " p e r i p h e r a l feedback o r c h a i n i n g " vs_ "preprogramming" model (Kent § M o l l , 1975).  Our d i s c u s s i o n b e g i n s w i t h c o n s i d e r a t i o n o f t h e theo-  r i e s which s u p p o r t an open-loop 1.61  hypothesis.  Open-Loop Models  As n o t e d above, an open-loop system s p e c i f i e s t h a t commands are i s s u e d to t h e a r t i c u l a t o r s a t r e g u l a r i n t e r v a l s t o produce s p e e c h , b u t t h a t feedback i s n o t employed t o r e g u l a t e i t s production.  One o f t h e more i n n o v a t i v e s t u d i e s o r i g i n a t e d  w i t h K o z h e v n i k o v and C h i s t o v i c h ale  (1965) , who t e s t e d the r a t i o n -  f o r u s i n g e i t h e r o f t h e two models t o account f o r t h e se-  quential generation  of s y l l a b l e s .  D e f i n i n g a "syntagma" as  a sentence o r phrase c o n n e c t e d by meaning and a r t i c u l a t i o n and pronounced on a s i n g l e o u t p u t , they v a r i e d t h e r a t e o f speech and s t r e s s o f the syntagma and found t h e s y l l a b l e t o be the u n i t which remained r e l a t i v e l y c o n s t a n t tion.  Their hypothesis  t i o n , the t o t a l v a r i a n c e  was t h a t i f an open loop i s i n operao v e r the time i n t e r v a l w i l l  than t h e sum o f the v a r i a n c e s t h e i r data support t h i s  under such v a r i a -  be l e s s  o f the component i n t e r v a l s , and  claim.  MacNeilage (1970) i n i t i a l l y s u p p o r t s an open-loop system, c l a i m i n g t h a t command p a t t e r n s wait  f o r information  i s s u e d to t h e muscles would not  from t h e a r t i c u l a t o r r e a c h i n g  a given  28  t a r g e t i n o r d e r t o c o n t r o l the f o l l o w i n g movement a p p r o p r i ately.  However, he p o i n t s out t h a t an open-loop system would  r e q u i r e s t o r a g e o f a v a s t amount o f i n f o r m a t i o n on phoneme-tophoneme t r a n s i t i o n s ; and s i n c e t h i s i s not p r a c t i c a l , he sugg e s t s t h a t c l o s e d - l o o p c o n t r o l i s more p r o b a b l e , based on n e u r o p h y s i o l o g i c a l r e s e a r c h on the gamma motor system ( c f . Section  1.3).  Fromkin's (1971) model o f speech p r o d u c t i o n shows a poss i b l e o r d e r i n g o f events accounts  i n g e n e r a t i o n o f an u t t e r a n c e  and  f o r p r o d u c t i o n o f e r r o r s , as w e l l as c o r r e c t u t t e r -  ances, but i t shows no r e l a t i o n s h i p o f these w i t h any back mechanism.  feed-  S i n c e t h e r e i s no mention o f feedback, espe-  c i a l l y c o n c e r n i n g e r r o r u t t e r a n c e s i n which the e r r o r i s "caught" and then c o r r e c t e d , i t can be assumed t h a t Fromkin's model i s more c l o s e l y a s s o c i a t e d w i t h an open-loop than, w i t h a c l o s e d - l o o p system. 1.62 The  Closed-Loop Models e a r l i e s t n o t i o n s o f a c l o s e d - l o o p model, f o l l o w i n g  cybernetic theory  ( i . e . , a system which employs feedback by  which t o modify subsequent p r o d u c t i o n s w i t h i n a g i v e n u t t e r ance) are p r o v i d e d by Lee  (1950) and F a i r b a n k s  proposed a system o f l o o p s :  (1954).  Lee  a r t i c u l a t i o n loops, monitoring  phonemes v i a t a c t i l e and k i n e s t h e t i c means, and v o i c e l o o p s , m o n i t o r i n g s y l l a b l e s v i a a u d i t o r y feedback; b o t h o f operate  on v o l i t i o n and r e f l e x systems.  Fairbanks  these inter-  p r e t e d the speech system as a c l o s e d - l o o p s e r v o s y s t e m ,  in  29  which the o u t p u t i s compared w i t h i n p u t v i a bone-conducted and a i r - c o n d u c t e d a u d i t o r y feedback and which m a n i p u l a t e s the  p r o d u c t i o n mechanism so t h a t o u t p u t w i l l have the same  f u n c t i o n a l form as i n p u t . Chase's  (1958) model o f speech p r o d u c t i o n l i k e w i s e i n -  c o r p o r a t e s a s e r v o s y s t e m and a u d i t o r y feedback and e v i n c e s the  same f l a w as F a i r b a n k s ' s model, namely t h a t m o n i t o r i n g  speech s o l e l y by means o f a u d i t o r y feedback would mean t h a t s p e a k i n g would be i m p o s s i b l e ( o r at l e a s t i n o r d i n a t e l y  dif-  f i c u l t ) i n an e x t r e m e l y n o i s y e n v i r o n m e n t , s i n c e feedback would be e f f e c t i v e l y masked.  As many who work i n i n d u s t r i a l  environments where t h e r e are e x c e p t i o n a l l y h i g h n o i s e l e v e l s will  a t t e s t , t h i s i s not the case. Kent and M o l l  (1975) p o s i t a feedback model which assumes  t h a t t i m i n g o f movements from h i g h e r c e n t r e s depends on e f f e r e n t and a f f e r e n t s i g n a l s r e c e i v e d from a p r e v i o u s a r t i c u l a t o r y movement, i n o r d e r t o c h a i n t o g e t h e r speech T h e i r "preprogramming", ent  or open-loop>  segments.  model assumes t h a t i n h e r -  t i m i n g c o n t r o l r e s u l t s i n the t i m i n g o f an a r t i c u l a t o r y  movement's b e i n g a f f e c t e d by a n o t h e r a r t i c u l a t o r y movement which o c c u r s e i t h e r b e f o r e o r a f t e r i t .  While they i n i t i a l l y  i n t e r p r e t the d a t a from t h e i r i n v e s t i g a t i o n of w o r d - i n i t i a l / s p r - / and / s p l - / c l u s t e r s i n terms o f a c l o s e d - l o o p system, Kent and M o l l note t h a t responses from t h i s feedback loop fail  t o r e a c h c o n s c i o u s n e s s and t h a t a r t i c u l a t i o n must t h e r e -  f o r e depend on " u n c o n s c i o u s feedback-mediated r e s p o n s e s " (1975, p. 319); i t i s not c l e a r from t h e i r argument how  feedback  30  might ever be a c o n s c i o u s response.  They r e c o n s i d e r  their  d a t a i n terms o f an open-loop model, which they c l a i m i s t h e o n l y way t o account f o r :  (a) v a r i a b l e d u r a t i o n o f / s / b e f o r e  /p/ i n / s p - / c l u s t e r s , and (b) the o r d e r i n g o f / s / - r e l e a s e upon t h e g e s t u r e f o r / p / - c l o s u r e , l i k e w i s e i n /sp-/ c l u s t e r s . However, they do n o t say how an open-loop system would accomplish this:  No r e s o l u t i o n i s f o r t h c o m i n g , except f o r t h e i n c i -  d e n t a l non-comment t h a t , whatever model one a d o p t s , i t w i l l be " c a p a b l e o f f i n e and a c c u r a t e c o n t r o l "  (Kent 5 M o l l , 1975,  p. 321). 1.63  Summary and D i s c u s s i o n  Ohala (1970) t r i e s t o c l e a r up some o f the m i s c o n c e p t i o n s s u r r o u n d i n g t h e r e s u l t s and i n t e r p r e t a t i o n o f Kozhevnikov and Chistovich s 1  logy employed  (1965) e x p e r i m e n t , commenting t h a t t h e methodocannot r e v e a l adequate i n f o r m a t i o n as t o the  p r e s e n c e o r absence o f feedback i n the t i m i n g o f speech.  He  proposes a r e i n t e r p r e t a t i o n o f t h e i r c l o s e d - and open-loop hypotheses:  The f i r s t i s a system which i s "'Timing Dominant'  ... i . e . , a system which m a i n t a i n s a t i g h t time s c h e d u l e p e r haps a t the expense o f p r e c i s e and thorough accomplishment o f the  g e s t u r e s " ; the second i s one which i s " ' A r t i c u l a t i o n  Dominant' ... i . e . , a system which m a i n t a i n s p r e c i s e and t h o r ough performance o f t h e g e s t u r e s no m a t t e r how much time i t takes"  ( O h a l a , 1970, p. 1 4 3 ) . He adds t h a t b o t h o f these  systems c o u l d e i t h e r employ o r n o t employ feedback i n d e t e r mining future a r t i c u l a t o r y events.  31  The major c r i t i c i s m l e v e l e d by Ohala (1970) the methodology  against  used by Kozhevnikov and C h i s t o v i c h (1965),  i n which s u b j e c t s were r e q u i r e d t o repeat the same u t t e r a n c e hundreds  o f times at d i f f e r e n t r a t e s o f speech, i s t h a t per-  haps the s u b j e c t s adopted a f i x e d rhythm and t h i s  could  a f f e c t the u n d e r l y i n g time s c h e d u l e and g e n e r a t i o n o f speech segments.  Under such c o n d i t i o n s an open-loop model, where  t i m i n g commands are sent at f i x e d i n t e r v a l s , i s more l i k e l y t o be adopted as an e x p l a n a t i o n o f t h e i r  findings.  In terms o f t h e i r d a t a a n a l y s i s , Ohala has  criticized  Kozhevnikov and C h i s t o v i c h f o r t h e i r r e l i a n c e on p o s i t i v e  and  n e g a t i v e c o v a r i a n c e s between phones i n the d e t e r m i n a t i o n o f which model s h o u l d be chosen; by c o v a r i a n c e , here i s meant t h a t i f an e r r o r i s made i n the d u r a t i o n o f a phone, e i t h e r p o s i t i v e l y or n e g a t i v e l y , i t i s compensated  f o r i n the f o l l o w -  i n g phone, w h i c h f i n i s h e s at the o r i g i n a l l y p l a n n e d t i m e , by b e i n g e i t h e r s h o r t e n e d or l e n g t h e n e d , r e s p e c t i v e l y .  Ohala  (1973) c l a i m s t h a t v a r i a t i o n s i n r a t e o f speech o f the t e s t i t e m s , i f c o n s i s t e n t l y y i e l d i n g p o s i t i v e c o v a r i a n c e s , would tend to s u p p o r t an open-loop model, which i s i n d e e d the one adopted by K o z h e v n i k o v and C h i s t o v i c h ; i f c o n s i s t e n t l y  nega-  t i v e c o v a r i a n c e s were o b t a i n e d , on the o t h e r hand', a c l o s e d loop model would suggest  itself.  Ohala (1970) a l s o q u e s t i o n s the a p p r o p r i a t e n e s s o f the c l o s e d - l o o p system f o r speech.  He p r e s e n t s s e v e r a l  arguments  i n f a v o u r o f such a system and then proceeds t o d i s p r o v e a l l o f them.  He does, however, c o n f i r m the p o s s i b i l i t y of the  32  use o f s h o r t - t e r m feedback to make q u i c k adjustments i n speech mum  (by r e c o u r s e to the r e s u l t s o f h i s experiment on maxi-  j aw opening and v e l o c i t y i n the p r o d u c t i o n o f i s o l a t e d  words; c f . O h a l a , 1970, pp.  122-141).  A model o f speech p r o d u c t i o n based on n e u r o p h y s i o l o g i c a l mechanisms w h i c h i n c o r p o r a t e s b o t h open-  and c l o s e d - l o o p s y s -  tems  He views the com-  has been p r o p o s e d by Abbs (1973).  p l e t e system as a " v a r i a b l e " s e r v o s y s t e m ( i . e . , one which can employ feedback depending on the system's r e q u i r e m e n t s ) .  He  c l a i m s t h a t the gamma motor system ( c f . S e c t i o n 1.31) i n v o l v e d i n feedback:  (1) m a i n t a i n s the l e n g t h o r r a t e o f  change o f l e n g t h o f a m u s c l e , (2) i s a c t i v e i n i n i t i a t i o n o f c o n t r a c t i o n , and  (3) p r o v i d e s a n t a g o n i s t i c a c t i o n s t o damp  movement and p r e v e n t o v e r s h o o t . A speech p e r c e p t i o n / p r o d u c t i o n model which i s an a c t i v e a n a l y s i s p r o c e s s a p p l i e d t o the speech s i g n a l i s the a n a l y s i s b y - s y n t h e s i s model p r o p o s e d by B e l l et a l . (1961).  The main  p a r t o f t h i s system i s a g e n e r a t o r capable o f s y n t h e s i z i n g a l l s i g n a l s t o be a n a l y s e d .  These s i g n a l s are compared w i t h  s i g n a l s to be a n a l y s e d and an e r r o r measure computed.  When  a s i g n a l i s s y n t h e s i z e d t h a t causes the e r r o r t o reach the smallest value, this signal i s stored. tem  Components o f the s y s -  are the f i l t e r s e t , spectrum g e n e r a t o r , comparator, and  strategy  component.  The d e s i g n e r s c l a i m t h a t t h i s system r e -  p r e s e n t s l i n g u i s t i c phenomena  at  v a r i o u s l e v e l s such as  a c o u s t i c , p h o n o l o g i c a l , m o r p h o l o g i c a l and s y n t a c t i c .  This  33  system i s mentioned here because i t c o n s i d e r s p r o d u c t i o n , p e r c e p t i o n , and feedback o f speech a l l i n one e f f i c i e n t model. On the assumption t h a t feedback may o r may n o t be i n v o l v e d i n t h e p r o d u c t i o n o f speech (depending on v a r i o u s cond i t i o n s , as y e t unknown), arguments f o r one type o f system or a n o t h e r are perhaps p r e m a t u r e , g i v e n the l a c k o f a p r o p e r empirical foundation.  Much more r e s e a r c h needs t o be c a r r i e d  out i n s e a r c h o f an answer t o the problem, and a t t e n t i o n s h o u l d now be devoted t o d e v i s i n g experiments which can adeq u a t e l y t e s t f o r t h i s i n t e r m i t t e n t feedback and t o d e t e r m i n i n g the r o l e i t p l a y s i n speech p r o d u c t i o n .  CHAPTER  2  STATEMENT OF THE PROBLEM There a r e few s t u d i e s which examine models of speech production i n conjunction with t h e i r p o s s i b l e neurophysiol o g i c a l b a s e s , and even fewer i n number a r e those i n v e s t i g a t i o n s which i n c o r p o r a t e c o n s i d e r a t i o n s o f feedback mechanisms i n t o such models. I f we c o n s i d e r p r o d u c t i o n o f a speech e r r o r as a moment a r y breakdown,  f o l l o w e d by a r e c a l i b r a t i o n o f the system  e n a b l i n g the c o r r e c t i o n o f an e r r o r , and i f we use such e r r o r s t o h y p o t h e s i z e about c e r t a i n a s p e c t s o f speech p r o - . d u c t i o n ( i n c l u d i n g feedback and n e u r o p h y s i o l o g i c a l mechanisms) , then perhaps i t might be p o s s i b l e t o p r o v i d e f u r t h e r i n s i g h t i n t o the p r o c e s s o f speech p r o d u c t i o n . Timing o f speech i s c o n s i d e r e d i n r e l a t i o n t o speech e r r o r s f o r the purpose o f d e t e r m i n i n g d i f f e r e n c e s i n d u r a t i o n of segments i n r e p e t i t i o n e r r o r s  ( o f the form /s*C*/ ... / s C / ) ,  between /s*/ and /C*/ i n an e r r o r p r o d u c t i o n and / s / and /C/ i n a c o r r e c t l y produced r e p e t i t i o n i m m e d i a t e l y f o l l o w i n g the error.  Because the e r r o r i s c o r r e c t e d i m m e d i a t e l y f o l l o w i n g  i t s commission  ( a l t h o u g h t h e r e may be a s l i g h t  hesitation,  to be d e s c r i b e d i n Chapter 4 ) , r a t e o f speech i s c o n s i d e r e d to remain c o n s t a n t and t h e r e f o r e not t o a f f e c t the l e n g t h o f c o n s o n a n t s .  significantly  Based on the f o r e g o i n g c o n s i d e r a -  t i o n s , comparisons a r e made between /s*/ and / s / and between /C*/ and /C/. 34  35  The  i n t e n t of the p r e s e n t  c a l l y s p e c i f i c aspects  study was  to examine s y s t e m a t i -  of speech e r r o r s through s t u d y i n g  l a t i o n s h i p s of w o r d - i n i t i a l f r i c a t i v e p l u s stop clusters,  re-  consonant  by:  (1) d e t e r m i n i n g  an e f f i c i e n t p r o c e d u r e f o r  speech e r r o r s and  generating  f o r t h e i r subsequent a n a l y s i s ;  (2) o b t a i n i n g a r e p r e s e n t a t i v e s a m p l i n g o f speech e r r o r s ' i n w o r d - i n i t i a l f r i c a t i v e p l u s stop  con-  son an t c 1 us t e rs ; (3) p r o v i d i n g a sample o f speech at normal  conversa-  t i o n a l r a t e c o n t a i n i n g no speech e r r o r s ; (4) c l a s s i f y i n g the types of speech e r r o r s found by c o n s u l t i n g a v a i l a b l e d e s c r i p t i v e accounts from previous  research;  (5) e v a l u a t i n g the d u r a t i o n and t i m i n g r e l a t i o n s h i p s o f c e r t a i n o f the w o r d - i n i t i a l c l u s t e r s under investigation; (6) c o n s i d e r i n g the e x p e r i m e n t a l  r e s u l t s i n terms o f  v a r i o u s models o f speech p r o d u c t i o n ,  feedback  mechanisms, and speech p e r c e p t i o n models.  CHAPTER  3  METHOD 3.1  Pilot  Studies  P r i o r to the main s t u d y , two p i l o t s t u d i e s were conducted i n o r d e r to a s c e r t a i n a r e a s o n a b l y o p t i m a l approach'to the c o l l e c t i o n and a n a l y s i s o f speech e r r o r s . 3.11 Subj e c t s .  P i l o t Study I S u b j e c t s f o r the f i r s t p i l o t s t u d y were f o u r female  u n i v e r s i t y s t u d e n t s , r a n g i n g i n age from 21 t o 25 y e a r s . A l l were n a t i v e speakers o f E n g l i s h w i t h no demonstrable h e a r i n g or  speech problems.  Stimulus M a t e r i a l s .  Three types of s t i m u l u s m a t e r i a l s were  used i n d i f f e r e n t c o m b i n a t i o n s to determine which woi*ld p r o duce the most f a t i g u e o f speech m u s c u l a t u r e and thus g i v e the g r e a t e s t number o f speech e r r o r s : (1)  The f i r s t p a r a g r a p h o f "The Rainbow Passage" ( c f . F a i r banks, 1960, p. 127; see Appendix A ) .  (2)  S i x o c c u r r e n c e s of each o f the c l u s t e r s / s p - / , / s t - / /sk-/  and  i n i n i t i a l p o s i t i o n i n words embedded i n t h r e e  s e p a r a t e paragraphs (see Appendix B ) . (3)  Twelve o c c u r r e n c e s o f each o f the w o r d - i n i t i a l  clusters  s p e c i f i e d i n (2) above i n words embedded i n t h r e e s e t s of s e n t e n c e s , each r e f e r r e d to here as a " t o n g u e - t w i s t e r " (see  Appendix C). 36  37 Procedure.  S u b j e c t 1 was i n s t r u c t e d t o read the "Rainbow  Passage" a t normal speed, then to read the t h r e e paragraphs f i v e times each c o n s e c u t i v e l y as f a s t as p o s s i b l e .  Subject  2 was i n s t r u c t e d t o read the "Rainbow Passage" a t normal speed, and then to read t h e t h r e e " t o n g u e - t w i s t e r s " times each as f a s t as she c o u l d .  Subject  3 was t o l d t o read  each o f the paragraphs once at normal speed and then times each as f a s t as she c o u l d .  five  five  F i n a l l y , S u b j e c t 4 was r e -  q u i r e d t o read each o f t h e " t o n g u e - t w i s t e r s " once at normal speed and then f i v e times each as q u i c k l y as p o s s i b l e . Results.  S u b j e c t 1 produced t h r e e e r r o r s ; S u b j e c t 2, t h i r -  teen e r r o r s ; Subject errors.  3, n i n e e r r o r s ; and S u b j e c t 4, f i f t e e n  Thus, more e r r o r s were produced by those  subjects  who had read the " t o n g u e - t w i s t e r s " than those who had n o t . In the l i g h t o f these r e s u l t s , i t was deemed n e c e s s a r y t o conduct a second p i l o t study u s i n g o n l y " t o n g u e - t w i s t e r s " as s t i m u l u s m a t e r i a l s , i n o r d e r to r e f i n e the e x p e r i m e n t a l procedures. 3.12 Subj e c t s .  P i l o t Study I I For t h i s study s u b j e c t s were two female u n i v e r s i t y  s t u d e n t s , b o t h 24 y e a r s o f age, n a t i v e speakers w i t h no demonstrable h e a r i n g o r speech Stimulus M a t e r i a l s .  of E n g l i s h  difficulties.  The s t i m u l u s m a t e r i a l s c o n s i s t e d o f the  t h r e e " t o n g u e - t w i s t e r s " d e s c r i b e d i n S e c t i o n 2.11 above and given  i n Appendix C.  Each sentence c o n t a i n e d  twelve  38 occurrences  o f one o f t h e w o r d - i n i t i a l c l u s t e r s / s p - / , / s t - /  or /sk-/ . Procedure.  Each s u b j e c t was r e q u i r e d to read each sentence  f i f t e e n times  as f a s t as p o s s i b l e .  Only the l a s t f i v e  repeti-  t i o n s were examined f o r speech e r r o r s , the f i r s t t e n product i o n s being  c o n s i d e r e d as t h e " f a t i g u i n g " p o r t i o n o f t h e  experiment. Results.  The number o f e r r o r s produced by s u b j e c t s  "tongue-twisters"  ( i n b o t h p i l o t s t u d i e s ) was g r e a t e r by a  f a c t o r o f two to one than those o b t a i n e d any  reading  o t h e r passage.  through the use o f  As s u c h , they were c o n s i d e r e d  t o produce  b e t t e r " f a t i g u i n g " e f f e c t s and were t h e r e f o r e chosen as s t i m u l u s m a t e r i a l s f o r the experiment 3.13 The  proper.  P i s cus s i o n types  o f e r r o r s produced by t h e s u b j e c t s i n the p i l o t  s t u d i e s c o u l d be c l a s s i f i e d as f o l l o w s : tion,  (b) p h o n e t i c  substitution,  (a) s y l l a b l e  (c) c l u s t e r  repetition,  (d) phoneme r e p e t i t i o n , and (e) phoneme p r o l o n g a t i o n . e r r o r s w i l l be d i s c u s s e d more f u l l y I t was f e l t  repeti-  These  i n Chapter 4.  t h a t r e a d i n g e r r o r s might have c o n t r i b u t e d t o  the p e r c e n t a g e o f the e r r o r s p r o d u c e d , but t h e r e appeared t o be no o b j e c t i v e way t o e x t r a c t speech e r r o r s under such c o n d i t i o n s . In o r d e r t o a v o i d the p o s s i b i l i t y o f r e a d i n g e r r o r s , g i v e n  that  the purpose o f t h e i n v e s t i g a t i o n was t o examine spontaneous productions,  i t was d e c i d e d  t o have the s u b j e c t s i n the main  39 study memorize the " t o n g u e - t w i s t e r s " r a t h e r than read them. Such a method has been d e s c r i b e d and employed by Kozhevnikov and C h i s t o v i c h (1965). 3.2  Main Study  Subjects.  S e l e c t e d f o r i n c l u s i o n i n the study were  twelve  u n i v e r s i t y s t u d e n t s , r a n g i n g from 22 to 33 years o f age, a l l o f whom were n a t i v e speakers  of English.  The h e a r i n g o f a l l  s u b j e c t s was j u d g e d t o be w i t h i n normal l i m i t s , and none had d e v i a n t a r t i c u l a t i o n p a t t e r n s o r anomalies o f f a c i a l musulature. Equipment. (a)  The equipment employed i n t h i s study i n c l u d e d :  For r e c o r d i n g :  a two-channel power s u p p l y  ( B r l i e l 6j K j a e r ,  Type 2803), a s s o c i a t e d w i t h a B r l i e l § K j a e r o n e - i n c h phone, Model 4145; and a S c u l l y Model 280-2 tape reproducer.  Recordings  micro-  recorder/  were made on Ampex 611 a u d i o t a p e at  7.5 i p s . (b)  For a n a l y s i s :  a Kay Sona-Graph, Model 7029A, a Siemens  O s c i l l o m i n k , and an Ampex M i c r o 50 c a s s e t t e  recorder/reproducer,  u t i l i z i n g s t u d i o - q u a l i t y magnetic tape. S t i m u l u s M a t e r i a l s and Procedure.  The s t i m u l u s m a t e r i a l s em-  p l o y e d i n c l u d e d t h e t h r e e " t o n g u e - t w i s t e r s " d e s c r i b e d above and g i v e n i n Appendix C. Each s u b j e c t was i n s t r u c t e d t o memorize one sentence a t a time.  When t h e s u b j e c t i n d i c a t e d t h a t she knew the passage  w e l l enough t o r e c i t e i t a l o u d w i t h o u t e r r o r o r p r o m p t i n g ,  40 t a p i n g began, d u r i n g which time a 12-inch mouth-to-microphone d i s t a n c e was m a i n t a i n e d . as  I n s t r u c t i o n s t o a l l s u b j e c t s were  follows: "Repeat the sentence once at normal c o n v e r s a t i o n a l r a t e i n a normal c o n v e r s a t i o n a l v o i c e , and then f i f t e e n times as f a s t as you c a n . "  The  s u b j e c t s f o l l o w e d t h i s procedure  f o r a l l t h r e e "tongue-  t w i s t e r s " , whereby t h e o r d e r o f p r e s e n t a t i o n o f the t h r e e sentences was v a r i e d randomly f o r a l l s u b j e c t s . 3.3  A n a l y s i s o f Data  Tapes and T r a n s c r i p t i o n . Tapes were t r a n s c r i b e d f o r a l l t w e l v e s u b j e c t s by the e x p e r i m e n t e r  using a modified v e r s i o n of the  I n t e r n a t i o n a l Phonetic Alphabet  (IPA).  This a n a l y s i s i n c l u d e d  the f i r s t p r o d u c t i o n a t normal speed and the f i f t e e n t e s t r e p e t i t i o n s , i n c l u d i n g any e r r o r s , t o g e t h e r w i t h t h e i r immediate phonetic contexts. mal  Tapes c o u l d be p l a y e d back e i t h e r a t nor-  speed o r at h a l f - n o r m a l speed, i n o r d e r t o f a c i l i t a t e  transcription.  E r r o r s were then coded (see Appendix D f o r  examples o f t r a n s c r i p t i o n and c o d i n g ) ; and where n e c e s s a r y , spectrograms were produced t o determine  more c l e a r l y  phonetic  s u b s t i t u t i o n s , e p e n t h e t i c phones, and r e v e r s a l s w i t h i n c l u s t e r s . Editing.  Because o f the e x t e n t o f t h e data a v a i l a b l e , o n l y data  from t h e s i x s u b j e c t s who made t h e most e r r o r s were e d i t e d and analyzed.  P h o n e t i c t r a n s c r i p t i o n s were v a r i f i e d by h a v i n g a  t r a i n e d p h o n e t i c i a n t r a n s c r i b e e r r o r s from these s i x s u b j e c t s . E d i t i n g was c a r r i e d out v i a t h e S c u l l y 280-2 tape r e c o r d e r / reproducer  i n c o n j u n c t i o n w i t h the Ampex M i c r o 50 c a s s e t t e  41  r e c o r d e r , the e x p e r i m e n t e r i s o l a t i n g the n o r m a l - c o n v e r s a t i o n a l rate r e p e t i t i o n  o f the " t o n g u e - t w i s t e r s " , a l l e r r o r s ,  and  t h e i r immediate c o n t e x t s . . Oscillograms.  E d i t e d d a t a were d i s p l a y e d v i s u a l l y on o s c i l l o -  grams, u s i n g the Siemens O s c i l l o m i n k .  This instrument d i s p l a y s  a speech s i g n a l t r a c e , d u p l e x o s c i l l o g r a m t r a c e , and a t r a c e o f the l o g o f average speech power. arrangement  W i t h i n the e x p e r i m e n t a l  i s a Revox Model A77 tape r e c o r d e r / r e p r o d u c e r ,  duplex o s c i l l o g r a p h , FrszSkj a e r - J e n s e n T r a n s - P i t c h m e t e r , and an intensity at t e n  o r speech power c i r c u i t .  O s c i l l o g r a m s were produced  cm/s.  I n s e r t F i g u r e 1 about here.  Segmentation.  Because  o f the r a p i d i t y  o f the s u b j e c t s '  speech, s e g m e n t a t i o n o f the o s c i l l o g r a m s p r o v e d somewhat d i f f i cult.  Gross s e g m e n t a t i o n was  c a r r i e d out f i r s t .  a c c o m p l i s h e d by marking o f f 10-cm The u t t e r a n c e on the tape was  T h i s was  s e c t i o n s on the o s c i l l o g r a m .  then t i m e d w i t h a stopwatch t o  a f i v e - s e c o n d mark, and at t h i s p o i n t the o s c i l l o g r a m  was  matched by c o u n t i n g w o r k i n g backwards from every f i v e to t h r e e to one second marks.  When a s u b j e c t ' s u t t e r a n c e s were segmented  at the g r o s s l e v e l , a f i n e r segmentation p r o c e d u r e was One the  o b j e c t i v e , o f the f i n e r segmentation was  conducted.  to e s t a b l i s h  time i n m i l l i s e c o n d s o f the /s/-segments p l u s s t o p  consonant  DUPLEX OSCILLOGRAPH TRANSTAPE RECORDER  PITCHMETER OSCILLOMINK SPEECH POWER METER  FIGURE  1.  B l o c k diagram o f i n s t r u m e n t a t i o n used t o produce o s c i l l o g r a m s .  42  43  in:  (a) t h e e r r o r segment, and (b) t h e c o r r e c t p r o d u c t i o n s  of the utterance.  S e l e c t i o n o f / s / + /C/ (stop)  many o f t h e d i f f i c u l t i e s  avoided  a s s o c i a t e d w i t h segmentation o f  g l i d e s , r e s o n a n t s , vowels and phonemes w i t h i n words which were e x c e s s i v e l y s h o r t e n e d , d i s t o r t e d o r o m i t t e d because o f the r a p i d i t y o f t h e s u b j e c t s ' 1959,  speech ( c f . L e h i s t e  § Peterson,  for details). I n i t i a l / s / p l u s stop consonant p l u s vowel  configurations  can be segmented w i t h o u t d i f f i c u l t y by e x a m i n a t i o n o f t h e speech wave t r a c e and the duplex o s c i l l o g r a m t r a c e .  The f i r s t  t r a c e , t h e speech s i g n a l , can be examined i n c o n j u n c t i o n  with  the n e g a t i v e a m p l i t u d e o f t h e d u p l e x , o r second, t r a c e t o det e r m i n e an / s / ; ( c f . L e h i s t e and P e t e r s o n , 1959).  The conso-  nants /p/, / t / and /k/ i m m e d i a t e l y f o l l o w i n g t h e / s / can a l s o be e a s i l y d i s t i n g u i s h e d , s i n c e the t r a c e o f t h e speech s i g n a l and  duplex both f o l l o w the z e r o - l i n e .  Vegetative  by t h e s u b j e c t s , such as s n o r t s , b r e a t h s , ing  sounds made  l i p smacks o r c l e a r -  o f t h e t h r o a t , made s e g m e n t a t i o n somewhat e a s i e r by adding  n a t u r a l pauses between o f t e n i n d i s t i n c t The  utterances.  maximum e r r o r measurement which r e s u l t e d from t h e  above p r o c e d u r e was t e n m i l l i s e c o n d s , when one s u b j e c t ' s were measured a g a i n by t h e e x p e r i m e n t e r . was  data  This maximum e r r o r  p r e s e n t on o n l y one o f f i f t y measurements made. U t t e r a n c e s which p r e s e n t e d problems i n s e g m e n t a t i o n  v e r y r a p i d speech, o r i n s t a n c e s  (e.g.,  o f dubious p h o n e t i c t r a n s c r i p -  t i o n s ) were, as n o t e d above, c l a s s i f i e d by examining wide-band spectrograms.  CHAPTER  4  RESULTS 4.0  Introduction U s i n g the " t o n g u e - t w i s t e r s " , each o f which c o n t a i n e d  t w e l v e i n s t a n c e s o f e i t h e r / s p - / , / s t - / o r / s k - / i n wordi n i t i a l position  (as d e s c r i b e d i n Chapter 3 and g i v e n i n  Appendix C ) , a sample o f the s i x s u b j e c t s ' speech under normal c o n v e r s a t i o n a l c o n d i t i o n s was o b t a i n e d .  U s i n g the  same " t o n g u e - t w i s t e r s " produced a t a s u b j e c t i v e l y  faster  r a t e o f speech was a procedure d e t e r m i n e d t o be e f f e c t i v e f o r g e n e r a t i n g speech e r r o r s i n the p i l o t s t u d i e s . pus o f speech e r r o r s i n v o l v i n g the w o r d - i n i t i a l  A cor-  clusters  was a l s o g a t h e r e d and s u b s e q u e n t l y c l a s s i f i e d . The s i x s u b j e c t s produced a t o t a l o f 228 e r r o r s , which c o u l d be c a t e g o r i z e d i n t o s i x t y p e s , as f o l l o w s  (see a l s o  Table 1 ) : (1)  Omission: spotted  (2)  Addition:  d e l e t i o n o f a phoneme o r s y l l a b l e ; e.g., -potted. e p e n t h e s i s o f a vowel o r consonant; e.g.,  skimpy -+ kskimpy. (3)  Substitution:  p h o n e t i c replacement o f d e v i a t i o n from  the t a r g e t phoneme; e.g., s k i n (4)  Checked H e s i t a t i o n :  skim.  i n s e r t i o n o f g l o t t a l s t o p as a  p a u s a l phenomenon; e.g., s c a l l i o n s -> s c a l l i o n s . ?  44  45  (5)  Prolonged H e s i t a t i o n :  unusual lengthening  or prolonga-  t i o n o f a phoneme; e.g., s t a l w a r t -* s t : a l w a r t . (6)  Repetition: production  reproduction  o f a word, when t h e f i r s t  i s h a l t e d f o l l o w i n g the f i r s t phoneme,  c l u s t e r , s y l l a b l e o r e n t i r e word; e.g., s p i r i t e d -*• spspirited.  I n s e r t T a b l e s 1 and 2 about h e r e .  More than f i f t y p e r c e n t o f a l l e r r o r s o b t a i n e d type ( 6 ) , i . e . , R e p e t i t i o n E r r o r s .  were o f  These i n t u r n c o u l d be  c l a s s i f i e d i n t o s i x s u b - t y p e s , when grouped a c c o r d i n g t o the r e p e a t e d segment o r segments, as f o l l o w s (1)  Phoneme R e p e t i t i o n :  production  (see T a b l e 2 ) :  o f the i n i t i a l / s / ,  f o l l o w e d by a pause and then p r o d u c t i o n  of the f u l l  word; i . e . , / s * (pause) sC.../. (2)  C l u s t e r R e p e t i t i o n w i t h a Pause:  production  with a  pause between t h e i n i t i a l c l u s t e r and r e p e t i t i o n o f t h e e n t i r e word; i . e . , /s*C* (pause) sC.../. (3)  C l u s t e r R e p e t i t i o n w i t h o u t a Pause:  same as ( 2 ) , b u t  w i t h o u t a pause between t h e e r r o r c l u s t e r and t h e repetition; (4)  i . e . , /s*C* sC.../.  /sCV/-Syllable ble,  Repetition:  production  o f an open s y l l a -  f o l l o w e d by a pause and t h e p r o d u c t i o n  word; i . e . , /s*C*V (pause) sC.../.  o f t h e whole  TABLE  Types and Numbers of Speech Errors Produced by Each Subject.  1.  Omission  Subj e c t  1 2  '  TOTAL '  1  2  5  18  32  8  2  2  1  11  28  52  1  4  1  3  15  . 24  6  19  • 33  59  2  1  17  11  37  1  2  1  13  24  10  13  56  118  228  1  5  5  6  7  TOTAL  25  Subj e c t  Repetition  2  4  2.  Prolong Hesitation  4  3  TABLE  Addition  E r r o r Type Substi- Checked tution Hesitation  1  6  Types and Numbers of Repetition Errors Produced by Each Subject R e p e t i t i o n E r r o r Type Cluster Cluster Syllable Syllable Phoneme w/ Pause No Pause sCVsCVC-  Entire Word  TOTAL  1  2  4  3  5  4  2  9  3  2  5  8  1  28  3  5  2  2  2  1  3  15  4  3  10  4  8  5  3  33  1  5  3  2  11  7  1  4  1  26  13  29  22  5 6 TOTAL  19  46  18  13 9  118  47  (5)  / s C V C / - S y l l a b l e R e p e t i t i o n . : p r o d u c t i o n of a c l o s e d s y l l a b l e , f o l l o w e d by a pause and the p r o d u c t i o n o f the e n t i r e word; i . e . , /s*C*VC (pause) sC.../.  (6)  Word R e p e t i t i o n :  p r o d u c t i o n of the e n t i r e word f o l l o w e d  by i t s r e p e t i t i o n . The  above r e p e t i t i o n e r r o r types were examined w i t h  r e s p e c t to the d u r a t i o n of the f r i c a t i v e p l u s s t o p consonant c l u s t e r s , as w e l l as to t h a t of the i n d i v i d u a l segments o f which they were composed. 4.1  C o n t r o l Group Data A speech sample at each s u b j e c t ' s normal r a t e of speech  was  o b t a i n e d ; and the d u r a t i o n s o f the /sC-/  clusters,  includ-  i n g i n t e r n a l segments, were then measured and a n a l y z e d .  The  d u r a t i o n d a t a thus o b t a i n e d p r o v i d e norms f o r t h i s study  and  and h e r e a f t e r r e f e r r e d to as the C o n t r o l Group Data (CGD). The  summary s t a t i s t i c s f o r these d a t a are p r e s e n t e d  i n Table  3.  I n s e r t Table 3 about h e r e .  The  CGD  were s u b j e c t e d to B a r t l e t t ' s t e s t f o r homogeneity  of v a r i a n c e a c r o s s s u b j e c t s :  The  chi-square values  d i d not exceed the c r i t i c a l v a l u e f o r s i g n i f i c a n c e i t was  obtained (p > .01);  t h e r e f o r e assumed t h a t the s u b j e c t s ' i n d i v i d u a l  c o u l d be p o o l e d f o r purposes of f u r t h e r e v a l u a t i o n and sis.  data analy-  TABLE 3.  C o n t r o l Group Data (Normal C o n v e r s a t i o n a l Rate) f o r  W o r d - I n i t i a l Consonant C l u s t e r s /sp-/, / s t - / , Means and Standard  D e v i a t i o n s o f Segmental D u r a t i o n s  2  Segment  /sk-/:  N=12  /s / P  X = sd=  76.67 17.23  /p/  X = sd=  80.83 12.22  /sp/  X = sd=  /s /  Subject 3  N=12  N=12  4  5  6  Mean  N=12  N=12  N=12  N=72  89.17 31.47  91.67* 74.17 31.86 • 21.09  97.64 39.56  90.83 18.81  82.50 23.01  91.67* 9-37  85.00 16.79  85.14 16.08  157.50 20.39  194.17* 230.83 57.91. 46.41  171.67 49.70  183.33* 159.17 34.20 23.14  182.78 46.90  X =  100.83  117.50  123.33  87.50  80.00  93.33  100.42  sd=  15.64  21.79  28.39  28.32  20.45  27.08  28.01  X =  40.83  39.17  43.33  57.50  '44.17  45.00  45.00  sd=  18.32  10.84  11.55  8.66  13.79  17.84  14.73  X =  141.67  156.67  166.67  145.00  124.17  138.33  145.42  sd=  29.80  21.03  35.51  29.70  24.29  24.43  30.11  /s /  X = sd=  93.33 24.25  107.50 26.33  125.00 25.05  85.00* 21.95  95.83 17.30  92.50 1.8.65  99.86 25.37  /k/  X =  57.50  63.33  61.67  61.67*  59.17  56.67  60.00  sd=  20.51  11.55  11.93  12.67  7.93  13.03  13.22  X =  150.83  170.83  186.67  146.67*  155.00  149.17  159.86  sd=  43.16  29.38  28.39  28.71  21.53  29.68  33.04  ft/  /st/  k  /sk/  114.17* 140.00 53.17 32.75  ( i n ms).  80.00* 11-28  * Due to subject error, N=ll for these entries; mean value added i n each case to yield N=12 i n order to standardize observations across a l l subjects. 48  49  S e v e r a l a n a l y s e s o f v a r i a n c e were c a r r i e d o u t : way c l a s s i f i c a t i o n demonstrated  A two-  significant differences  among s u b j e c t s , segments and the i n t e r a c t i o n o f these (see Table 4 ) ; but w i t h r e s p e c t t o s u b j e c t - b y - c l u s t e r i n t e r a c t i o n , no such s i g n i f i c a n c e c o u l d be found  (see Table 5 ) . Under  each o f these a n a l y s e s , a Newman-Keuls t e s t was c a r r i e d o u t , which  ( w i t h p < .05)  i n d i c a t e d t h a t the i n d i v i d u a l  clusters  comprised homogeneous s u b s e t s , as d i d each o f the stop cons o n a n t s , whereby a l l i n i t i a l same subset  /s/-segments f e l l  i n t o the  (see Tables 4a and 5 a ) .  I n s e r t T a b l e s 4 - 7a about h e r e .  One-way a n a l y s e s o f v a r i a n c e were a l s o c a r r i e d out w i t h the d a t a from a l l s u b j e c t s p o o l e d .  As e x p e c t e d , t h e segments  and c l u s t e r s showed s i g n i f i c a n t d i f f e r e n c e s , and the NewmanKeuls t e s t  ( w i t h p_ < .05) demonstrated  subset groupings  the same homogeneous  as were found i n the two-way  classification  (see T a b l e s 6 and 6a, 7 and 7 a ) . A g e n e r a l i n t e r p r e t a t i o n o f the CGD can be made' by cons i d e r a t i o n o f the o v e r a l l means (as g i v e n i n the l a s t column of  Table 3 ) , which are p r e s e n t e d g r a p h i c a l l y i n F i g u r e 2.  The d u r a t i o n of / s / b e f o r e any o f the stop consonants a p p r o x i m a t e l y 100 ms, w i t h / s / b e f o r e /p/ b e i n g shorter.  was  slightly  The mean d u r a t i o n o f t h e s t o p consonants  ranges  from 45-85 ms, w i t h / t / h a v i n g t h e s h o r t e s t and /p/ h a v i n g  TABLE  4.  Summary of Analysis of Variance:  Control Group Data --  Cluster Segments and Subjects.  Source o f Variation  Sum o f Squares  S u b j e c t s (S) Segments (P)  29585.18 198937.95  5 5  5917.04 39787.59  12.566 84.497  <.0001 . <.0001  S x P Error  42581.48 186466.65  25 396  1703.26 470.88  3.617  <.0001  TABLE  4a.  Mean Square  d.f.  F  Newman-Keuls Summary Table: Control Group Data ( p < .05) -Cluster Segments and Subjects.  Homogeneous Subsets Subj e c t s  (1) (2) (3)  P  Cluster (1)  6, 1, 5, 4 2  /s /, /s /, /s /  (2) / t / (3) /k/  3  (4)  50  Segments  /p/  TABLE  5.  Summary of Analysis of Variance: Clusters and Subjects.  Sum o f Squares  Source o f Variation Subjects Clusters S x C Error  TABLE  5a.  (S) (C)  59170.01 51112.03 13860.18 225049.98  A .-FX . U  5 2 10 198  Newman-Keuls Summary Table:  Control Group Data --  Mean Square  11834.07 10.412 25556.02 22.484 1386.02 1.219 1136.62 .  Homogeneous Subsets Clusters  (1)  6, 1, 5,. 4  (1) / s t /  (2)  2  (2) / s k /  (3)  3  (3) / s p /  51  P < .0001 < .0001 > .25  Control Group Data ( p < .05)  Clusters and Subjects.  Subjects  r  TABLE  6.  Summary of Analysis of Variance:  Control Group Data --  Cluster Segments, One-Way C l a s s i f i c a t i o n .  Sum o f Squares  d.f.  Segments  198937.95  5  39787.59  Error  258633.31  426  607.12  Source o f Variation  TABLE  6a.  Newman-Keuls Summary Table: Cluster Segments.  Homogeneous S u b s e t s :  (1)  Mean Square  (2)  /t/  (3)  /k/  (4)  /p/  k  Segments  t  52  65.535  P  < .0001  Control Group Data ( p < .05 ) --  / s / ,/ s / , / s / p  F  TABLE  7.  Summary of Analysis of Variance:  Control Group Data -  Clusters, One-Way C l a s s i f i c a t i o n .  Source o f Variation  Sum o f Squares  Clusters Error  TABLE. 7a.  ,  '  Mean Square  51112.03  2  25556.02  298080.53  213  1399.44  f a , t  Newman-Keuls Summary Table: Clusters.  Homogeneous  Subsets:  (1) / s t / (2)  /sk/  (3)  /sp/  53  p — 18.26  P  < .0001  Control Group Data (p < .05 ) —  Clusters  54  the l o n g e s t d u r a t i o n .  The c l u s t e r s range i n mean d u r a t i o n  from about 145 ms f o r / s t / t o 183 ms f o r / s p / , w i t h / s k / i n between a t 160 ms.  The d u r a t i o n o f t h e c l u s t e r s i s c o n s i s -  t e n t l y o f t h e same o r d e r as w i t h the i n d i v i d u a l stop segments, due t o t h e s i m i l a r i t y o f the d u r a t i o n s o f t h e / s / segments.  • I n s e r t F i g u r e 2 about h e r e .  4.2  Experimental The  s i x Repetition Error classes  perimental for  Group Data ( h e r e a f t e r c a l l e d Ex-  Groups #1 - #6) were examined s e p a r a t e l y by s u b j e c t  segments and c l u s t e r s , t h e summary s t a t i s t i c s  are p r e s e n t e d  f o r which  i n T a b l e 8.  I n s e r t Table 8 about, h e r e .  In E x p e r i m e n t a l  Group #1 (Phoneme R e p e t i t i o n ) , / s / i s  c o n s i s t e n t l y s h o r t e r the / s * / ( i . e . , the e r r o r p r o d u c t i o n ) , r e g a r d l e s s o f t h e stop consonant which f o l l o w s .  The segment  /p/  i s t h e l o n g e s t stop consonant (ca. 100 ms), f o l l o w e d by  /k/  (87.5 ms). and f i n a l l y by /%/ (50 ms); t h i s i s c o n s i s t e n t  w i t h the f i n d i n g s f o r the CGD. cluster durations  The r e l a t i v e o r d e r i n g o f the  f i n d s / s k / t o have the l o n g e s t mean dura-  t i o n and / s t / t h e s h o r t e s t ; t h i s d i f f e r s from t h e CGD i n t h a t  200  DURATION 100 0  ( i n ms ) 100  200  s|  It  S.l k  si  s! s  K  1 I  s  I  S.2  , It  s s  "  J  S.3  fk  s s  S.4  S.5 J"  ]p  s  ]p  s s  FIGURE 2.  S.6  MEAN  C o n t r o l Group Data: Segment and C l u s t e r Duration. Mean v a l u e s f o r each s u b j e c t . 55  TABLE  8.  Summary S t a t i s t i c s f o r Segmental and Cluster Durations (in ms), i n Six Repetition Error Groups (termed Experimental Groups). ( Mean / Standard Deviation / Number of Observations )  Experimental  * *  s*t*  t  st  s*: 136.67/ 66.58/ 3 s: 90.00/ 10.00 C*: C: 100.00/ 50.00 s*C*: sC: 190.00/ 45.83  127.50/ 92.15/ 4 107.50/ 57.37  #2: Cluster Repetition (with Pause)  s*: s: C*: C: s*C*: sC:  #3: Cluster Repetition (No Pause)  #4:  #1: Phoneme Repetition (s* - sC)  sCV-Syllable Repetition  #5: sCVC-Syllable Repetition  #6:. Word Repetition  s*k* , sk 162.50/154.17/12 154.17/122.14  50.00/ 24.49  87.50/ 61.52  157.50/ 71.36  241.67/136.90  120.00/ 62.05/ 5 68.00/ 16.43 208.00/110.77 82.00/ 4.47 328.00/129.31 150.00/ 15.81  128.00/ 35.64/ 5 100.00/ 40.00 318.00/261.29 52.00/ 19.24 446.00/273.28 152.00/ 48.68  118.75/ 45.73/16 116.25/ 31.60 229.37/227.29 66.87/ 29.15 348.12/242.63 183.12/ 48.82  s*: s: C*: C: s*C*: sC:  128.00/ 48.68/ 5 118.00/ 65.35 462.00/308.50 45.00/ 25.50 590.00/543.29 163.00/ 85,41  140.00/ 56.57/ 2 95.00/ 21.21 270.00/296.98 40.00/ 28.28 410.00/240.42 135.00/ 7.07  158.33/105.53/ 6 131.67/ 36.01 376.67/164.03 65.00/ 10.49 535.00/231.58 196.67/ 41.79  •s*: s:  118.33/ 51.15/ 6 116.67/ 54.65  87.69/ 33.20/13 90.77/ 33.78  103.00/ 32.68/10 102.00/ 39.38  C*: 160.83/154.93 C: 70.00/ 17.89 s*C*: 279.17/156.67 sC: 186.67/ .61.21 s*: s:  116.67/ 46.19/ 3 120.00/ 50.00  79.23/ 43.08/ 166.92/ 133.85/  57.22, 20.97 81.69 50.42  92.00/ 60.00/ 195.00/ 162.00/  41.04 23.09 54.42 53.71  80.00/ 19.27/ 8 105.00/ 51.27  121.82/ 47.08/11 105.45/ 26.22  C*: 123.33/ 77.67 C: 90.00/ 26.46 s*C*: 240.00/122-. 88 sC: 210.00/- 72.11  .40.00/ .13.09 41.25/ 16.42 120.00/ 22.04 146.25/ 55.79  148.18/254.67 45.45/ 13.68 270.00/286.23 150.91/ 35.34  s*: s: C*: C: s*C*: sC:  60.00/ 0.00/ 2 110.00/ 14.14 55.00/ 7.07 80.00/ 28.28 115.00/7.07 190.00/ 14.14  108.00/ 32.71/ 5 108.00/ 22.80 82.00/ 17.89 70.00/10.00 190.00/47.43 178.00/ 30,35  115.00/ 49.50/ 2 75.00/21.21 115.00/ 7.07 80.00/ 28.28 230.00/ 56.57 155.00/ 49.50  56  57  /sk/ and /sp/ are r e v e r s e d i n o r d e r w i t h r e s p e c t t o d u r a t i o n . Because o f the p h o n e t i c shape o f t h i s e x p e r i m e n t a l no segment /C*/  or c l u s t e r /s*C*/ e x i s t s  In E x p e r i m e n t a l  Group #2  group,  (see a l s o F i g u r e 4 ) .  (Cluster Repetition with a  P a u s e ) , the e r r o r p r o d u c t i o n s / s * / , /C*/  and /s*C*/ are a l l  l o n g e r i n d u r a t i o n t h a n the c o r r e c t e d r e p e t i t i o n s / s / , /C/ and /sC/,  r e s p e c t i v e l y . C o n s i d e r i n g the e r r o r c l u s t e r s :  i s the l o n g e s t (446 ms)  /s*t*/  (328 ms),  a f i n d i n g which i s not c o n s i s t e n t w i t h the  experimental tion  and /s*p*/ the s h o r t e s t  (183 ms)  groups.  The  c l u s t e r /sk/ has  the l o n g e s t  and /sp/ the s h o r t e s t (150 ms),  c o n s i s t e n t w i t h the CGB Experimental  other dura-  which i s not  (see F i g u r e 3 ) .  Group #3  (Cluster R e p e t i t i o n without  Pause) p a t t e r n s a f t e r the above group, where /s*/,  a  /C*/  and  /s*C*/ are c o n s i s t e n t l y l o n g e r i n d u r a t i o n than / s / , /C/ /sC/,  respectively.  In t h i s group, /C*/  l o n g e r than i n - a n y o t h e r e x p e r i m e n t a l /s*p*/  i s the l o n g e s t (590 ms)  (135 ms)  is definitively  group:  the  cluster  and / s * t * / the s h o r t e s t  (410 ms), w h i l e /sk/ i s the l o n g e s t shortest  and  (197 ms)  and / s t / the  o f the c o r r e c t e d p r o d u c t i o n s .  The  /.st/ i s the o n l y one which i s c o n s i s t e n t w i t h the CGD  cluster (see  also Figure 3). Experimental  Group #4 . (/sCV/.-Syllable R e p e t i t i o n ) a l s o  shows a l l e r r o r segments t o be l o n g e r than n o n - e r r o r  segments.  Here, / s * p * / and /sp/ are the l o n g e s t and / s * t * / and / s t / the shortest  clusters.  58 In E x p e r i m e n t a l the n o n - e r r o r  Group #5 ( / s C V C / - S y l l a b l e R e p e t i t i o n ) ,  segments and c l u s t e r s a r e l o n g e r than t h e  e r r o r segments and c l u s t e r s , r e s p e c t i v e l y . T h i s from a l l o t h e r groups d i s c u s s e d thus f a r .  differs  Of the n o n - e r r o r  p r o d u c t i o n s , /s^/, /p/ and / s p / have the l o n g e s t d u r a t i o n s , w h i l e /|:/> /k*/ and /s*k*/ show the l o n g e s t d u r a t i o n s o f s  the e r r o r segments and c l u s t e r s Experimental  (see F i g u r e 3 ) .  Group #6 (Word R e p e t i t i o n ) demonstrates  /s z /, ft/ and / s t / t o have t h e l o n g e s t d u r a t i o n s , w h i l e /sp /, /p/ and / s p / have the s h o r t e s t . /p*/  Of the e r r o r d a t a , / s * / ,  and /s*p*/ a r e the l o n g e s t , w h i l e / s * / , / t * / and / s * t * /  are the s h o r t e s t , thus c o n f l i c t i n g w i t h the r e s u l t s f o r the CGD (see a l s o F i g u r e 4 ) .  '  I n s e r t F i g u r e s 3 and 4 about h e r e .  I n s e r t Table  9 about h e r e .  In o r d e r t o g e n e r a l i z e o b s e r v a t i o n s , the d a t a from Exp e r i m e n t a l Groups #2-#5 were p o o l e d , the r e s u l t s o f w h i c h are p r e s e n t e d  i n Table 9.  T h i s summary i l l u s t r a t e s  that  /s*p*/ a t 368 ms and /sp/ a t 174 ms e x h i b i t the l o n g e s t c l u s t e r d u r a t i o n s , w h i l e / s * t * / a t 2 21 ms and / s t / a t 141 ms  FIGURE 3.  E x p e r i m e n t a l Group's #2-#5: Segment and C l u s t e r D u r a t i o n . Mean v a l u e s f o r e r r o r and c o r r e c t p r o d u c t i o n s . 59  DURATION  200  100  100  200  ( i n ms )  — I  I  —I—  -  300  —I—  .'V.'.'.'.'.'.'.'.'.'.V.  ]p  E  EG#1  (('••III,  M y m  i  n  t  u n a r i f i  1  r r r y u  II/I  t r i i i t w  • » . . • . . . . . . „ . . < > . ",ir,i-n-itiiii r't,iii,ft.rt,in|  1  FIGURE 4,  r  r  EG#6  E x p e r i m e n t a l Groups #1 and #6: Segment and C l u s t e r D u r a t i o n . Mean v a l u e s f o r e r r o r and correct productions.  60  400  —I  TABLE  9.  Summary of Repetition Error Data for Experimental Groups #2-#5: Segmental and Cluster Durations (in ms).  Segment  (Mean / S.D. / N )  Segment  Error Production  /s*/  121,05 / 48.64 / 19  /s /  104.74 /  51.25 / 19  /s*/  96.43 / 36.54 / 28  /s /  96.79 /  38.50 / 28  55.75 / 43  /s^/  Correct Production  /s*/  121.40 /  /p*/  246.58 / 222.49 / 19  /p/  69.74 /  24.41 / 19  /t*/  124.29 / 162.74 / 28  ft/  43.93 /  19.12 / 28  /k*/  197.21 / 213.81 / 43  /k/  59.53 /  23.50 / 43  /s*p*/  367.63 / 240.61 / 19  /sp/  174.47 / 61.30 / 19  /s*t*/  220.71 / 180.96 / 28  /st/  140.71 /  /s*k*/  318.60 / 242.54 / 43  /sk/  171.86 / 47.42 / 43  61  112.33 / 33.23 / 43  48.45 / 28  62 e x h i b i t the s h o r t e s t ; t h i s i s c o n s i s t e n t w i t h the CGD f i n d ings.  The segments / s | / a t 121 ms and / s ^ / a t 112 ms a r e  o n l y s l i g h t l y l o n g e r i n t h e l a t t e r case than / s * / a t 121 ms and /s / a t 105 ms, w i t h /s*/ a t 96 ms and /s^/ a t 97 ms r e maining  the s h o r t e s t .  A l s o c o n s i s t e n t w i t h t h e CGD i s t h e  f i n d i n g t h a t /p*/ a t 247 ms and /p/ a t 70 ms a r e t h e l o n g e s t stop segments, .whereby  It*I  a t 124 ms and / t / a t 44 ms a r e  the s h o r t e s t . The (1)  f o l l o w i n g g e n e r a l o b s e r v a t i o n s may be made:  Segments and c l u s t e r s i n t h e e r r o r , o r f i r s t ,  productions  are l o n g e r than t h e i r r e s p e c t i v e c o u n t e r p a r t s i n the c o r r e c t e d , or second, p r o d u c t i o n s . (2)  The s h o r t e s t c l u s t e r s a r e / s * t * / and / s t / , which a l s o  c o n t a i n t h e s h o r t e s t segments / s * / , / t * / , /s / and / t / . (3)  The l o n g e s t /s/-segments a r e /s£/ and / s ^ / *  (4)  The l o n g e s t stop consonants a r e /p*/ and /p/.  (5)  The l o n g e s t c l u s t e r s a r e / s * p * / and / s p / . I f we c o n s i d e r the r e s u l t s o f o v e r a l l means o b t a i n e d i n  the c o r r e c t p r o d u c t i o n s  i n l i g h t o f t h e CGD f i n d i n g s , we note  that: (1)  The d u r a t i o n o f / s / b e f o r e any s t o p consonant was approx-  i m a t e l y 100 ms i n the CGD and 104 ms i n t h e E x p e r i m e n t a l  Group  Data (EGD). (2) and (3) EGD.  The d u r a t i o n o f t h e stop consonant was 63 ms i n t h e CGD 53 ms i n t h e EGD. The d u r a t i o n o f t h e c l u s t e r was 163 ms f o r both CGD and  63  The  r a n k i n g o f the segments and c l u s t e r s w i t h i n t h e i r r e -  s p e c t i v e groups a l s o remains about the same.  An  interesting  o b s e r v a t i o n might be made r e g a r d i n g the s i m i l a r i t y means:  of  Under c o n t r o l c o n d i t i o n s , s u b j e c t s were s p e a k i n g  a normal r a t e , w h i l e the same s u b j e c t s , when s p e a k i n g experimental  c o n d i t i o n s , were s p e a k i n g  segments and c l u s t e r s s h o r t e r than those o f the CGD; not the case.  at  under  as f a s t as they c o u l d .  T h i s s h o u l d , i t would seem, make the d u r a t i o n s of the  such was  these  I t i s reasonable  EGD but  to suppose from  these r e s u l t s t h a t once an e r r o r i n a f i r s t p r o d u c t i o n i s made, perhaps the r a t e r e t u r n s to the normal c o n v e r s a t i o n a l r a t e u n t i l the s u b j e c t can once a g a i n p i c k up  speed.  Summary s t a t i s t i c s were a l s o d e r i v e d f o r the" pause, or d e l a y t i m e , between e r r o r and c o r r e c t p r o d u c t i o n s . statistics  These  show t h a t the pause can be e l i m i n a t e d , but t h a t a  l e n g t h e n i n g of the c o n s o n a n t " b e f o r e  the pause, when i t o c c u r s ,  can have a mean v a l u e as g r e a t as 967 ms Repetition).  (such as i n Phoneme  D i s r e g a r d i n g the cases where no pause o c c u r s ,  the pause can be as s h o r t as 20 ms or as l o n g as 6550 ms ( w i t h l i t t l e or no l e n g t h e n i n g o f the segment b e f o r e i t ) .  CHAPTER  5  DISCUSSION 5.0  General C o n s i d e r a t i o n s The  i n t e n t o f the p r e s e n t study was  to examine  system-  a t i c a l l y s p e c i f i c aspects o f speech e r r o r s through s t u d y i n g r e l a t i o n s h i p s o f word i n i t i a l clusters.  The  f r i c a t i v e p l u s s t o p consonant  c a t e g o r i e s i n t o which  e r r o r u t t e r a n c e s are  c l a s s i f i e d i n the l i t e r a t u r e p e r t a i n i n g t o speech e r r o r s ( s p e c i f i c a l l y Boomer § L a v e r , 1968) c r i b e e r r o r s produced to  were not adequate t o des-  by s u b j e c t s i n t h i s study.  m i s o r d e r i n g , o m i s s i o n and replacement  o f segments ( c f .  Boomer $ L a v e r , 1968), a d d i t i o n , h e s i t a t i o n and e r r o r s were produced.  In a d d i t i o n  repetition  These l a t t e r c a t e g o r i e s were found  c o n s u l t i n g the l i t e r a t u r e on d e l a y e d a u d i t o r y feedback ami wert adapted  by  (DAF)  from t h e c a t e g o r i e s s e t up by F a i r b a n k s  and  Guttman (1958) , s i n c e they p r o v e d to be the most a p p l i c a b l e to  the p r e s e n t  study.  Approximately  fifty  p e r c e n t o f a l l e r r o r s produced  s u b j e c t s i n t h i s study were o f the r e p e t i t i o n t y p e . i z a t i o n o f ..these e r r o r s was  by-  Categor-  based on p h o n e t i c t r a n s c r i p t i o n s  c a r r i e d out by the e x p e r i m e n t e r  and a t r a i n e d p h o n e t i c i a n  and supplemented by s p e c t r o g r a p h i c a n a l y s i s where n e c e s s a r y (for  a l i s t o f the e r r o r s and the p h o n e t i c  see Appendix D).  transcriptions,  T h i s y i e l d e d s i x c a t e g o r i e s of r e p e t i t i o n  e r r o r s based on t h e i r p h o n e t i c  64  forms.  65 S p e c u l a t i o n as to why  r e p e t i t i o n e r r o r s are  corrected  and e r r o r s i n the o t h e r c a t e g o r i e s are not l e d to of the f i r s t p r o d u c t i o n s  for phonetic  deviancies  the subsequent c o r r e c t i o n p r o d u c t i o n s . only about one  I t was  examination vis-a-vis  found t h a t  t h i r d o f the r e p e t i t i o n e r r o r s c o u l d be  s i d e r e d as c o r r e c t i o n s because of p h o n e t i c the f i r s t , or e r r o r , p r o d u c t i o n .  The  con-  abnormalities i n  phenomenon o f  excessive  l e n g t h a s s o c i a t e d w i t h the i n i t i a l c l u s t e r and i t s component segments was phonetic  o f t e n n o t e d , but i t was  abnormality.  I t was  not c o n s i d e r e d  o b s e r v e d t h a t the f i r s t phoneme  o r c l u s t e r i n the e r r o r s y l l a b l e o r word was in  as a  somewhat l o n g e r  d u r a t i o n than might have been s u b j e c t i v e l y expected.  This  o b s e r v a t i o n l e d i n t u r n to comparison of the d u r a t i o n s of the initial  c l u s t e r s and t h e i r segments i n the e r r o r p r o d u c t i o n  w i t h the i m m e d i a t e l y tion.  f o l l o w i n g c l u s t e r p r o d u c t i o n , or c o r r e c -  In o r d e r to measure o b j e c t i v e l y and compare these  dura-  t i o n s , o s c i l l o g r a m s were produced-and measured f o r each subj e c t ' s normal p r o d u c t i o n o f the " t o n g u e - t w i s t e r s " , t h e n f o r each s u b j e c t ' s e r r o r s which o c c u r r e d ductions. analysis  The  i n subsequent r a p i d p r o -  r e s u l t s o b t a i n e d were s u b j e c t e d to  (as d e t a i l e d i n the p r e v i o u s  chapter).  s p e c i f i c to the c o n t r o l group d a t a w i l l 5.1  statistical Findings  be d i s c u s s e d  first.  D i s c u s s i o n o f the C o n t r o l Group The  a n a l y s i s o f v a r i a n c e c a r r i e d out on the c o n t r o l group  d a t a showed s i g n i f i c a n t d i f f e r e n c e s between s u b j e c t s and tween phonemes, as w e l l as c l u s t e r s ( c f . Tables  4-7).  The  be-  66 Newman-Keuls t e s t grouped  f o u r o f the s u b j e c t s i n t o one  homogeneous s u b s e t , w h i l e S u b j e c t 2 and S u b j e c t 3 were each s e p a r a t e l y grouped.  The s e g r e g a t i o n o f t h e s e two s u b j e c t s  may have r e s u l t e d from the f a c t t h a t b o t h spoke w i t h subj e c t i v e l y more p r e c i s e a r t i c u l a t i o n and somewhat more s l o w l y than the o t h e r s u b j e c t s (but a l s o d i f f e r e n t l y enough from one another t o be grouped s e p a r a t e l y ) .  Such f a c t o r s would  tend  to l e n g t h e n segments and c l u s t e r s i n the speech o f these two s u b j e c t s and thus account f o r the d i f f e r e n c e s i n the NewmanK e u l s t e s t ( c f . Tables 4a and 5 a ) . The f o u r s i g n i f i c a n t s u b s e t s f o r segments e x h i b i t e d by the Newman-Keuls t e s t subsets f o r c l u s t e r s  ( c f . T a b l e s 4a and 6a) and the t h r e e ( c f . Tables 5a and 7a) s e g r e g a t e (a)  a l l /s/-segments as a group  from /p/, ft/ and /k/, each o f  which are a l s o grouped s e p a r a t e l y , and (b) t h e c l u s t e r s , / s t / from /sk/ from ./sp/.  E x a m i n a t i o n o f the means  ( c f . Table 3)  i n d i c a t e s t h a t / s / b e f o r e /p/ i s s l i g h t l y s h o r t e r than / s / b e f o r e / t / . o r /k/, w i t h / t / b e i n g the s h o r t e s t s t o p and /p/ the l o n g e s t , c o n s i s t e n t w i t h the d a t a r e p o r t e d by Schwartz (1970).  Based on the means and t h e Newman-Keuls t e s t  group-  ings i n t h i s study, i t i s reasonable to speculate t h a t , since d u r a t i o n o f the s i b i l a n t i s s i m i l a r i n each c o n t e x t , i t i s the stop consonant which u l t i m a t e l y determines the d u r a t i o n o f the c l u s t e r as a whole.  . Indeed, when one examines the means  and the subset o r d e r i n g s f o r the s t o p consonants  :  and f o r the  c l u s t e r s , the same r e l a t i o n s h i p h o l d s ; i . e . , /p/ i s . l o n g e r than ,/k/, which i s l o n g e r than / t / , and / s p / i s l o n g e r than / s k / , which i s l o n g e r than / s t / .  67  The  above f i n d i n g s are i n agreement w i t h those  Borden and Gay  of  (1975) w i t h r e s p e c t to the g r o u p i n g s and r e -  l a t i v e o r d e r i n g s o f segments c o m p r i s i n g w o r d - i n i t i a l  clusters;  due perhaps .to t h e i r s u b j e c t s ' p r o d u c i n g words i n i s o l a t i o n , t h e i r v a l u e s f o r the d u r a t i o n s o f these segments are somewhat l a r g e r i n a l l cases.  I n c o n s i s t e n t w i t h t h e i r f i n d i n g s i s the  r e l a t i v e o r d e r i n g of c l u s t e r l e n g t h s , s i n c e t h e i r data  indi-  cate t h a t /sk/ i s s l i g h t l y l o n g e r than / s t / , which i s l o n g e r than /sp/. s i b i l a n t may is  T h i s suggests t h a t f o r t h e i r t h r e e s u b j e c t s the be a g r e a t e r d e t e r m i n e r o f c l u s t e r l e n g t h , w h i c h  i n c o n t r a s t w i t h the r e s u l t s of the p r e s e n t  5.2  D i s c u s s i o n o f the E x p e r i m e n t a l In  study.  Groups  e x p e r i m e n t a l groups #l-#6 the d u r a t i o n o f the  or e r r o r , p r o d u c t i o n was rected, production.  first,  c o n t r a s t e d w i t h the second, or c o r -  Because o f the d i f f e r e n c e s i n r a t e o f  speech and o t h e r u n c o n t r o l l e d v a r i a b l e s , these speech e r r o r data cannot be l e g i t i m a t e l y compared w i t h the c o n t r o l group f i n d i n g s ; however, the g e n e r a l t r e n d s i n the two groups o f d a t a can be compared i n o r d e r t o a s c e r t a i n whether s i m i l a r i t i e s exist. E x p e r i m e n t a l groups #2-#5 were combined i n o r d e r t o observe more g e n e r a l t r e n d s i n the data. #1 was  Experimental  not used, s i n c e i t c o n t a i n e d no e r r o r c l u s t e r ;  e x p e r i m e n t a l group #6 was  group and  not c o n s i d e r e d because i t i n v o l v e d  r e p e t i t i o n o f a whole word r a t h e r than o f an i n i t i a l  cluster  68  or s y l l a b l e .  Groups #1 and #6 a l s o c o n t a i n e d s.mall numbers  o f o b s e r v a t i o n s and were thus l e s s l i k e l y to a f f e c t group trends. As mentioned p r e v i o u s l y , s u b j e c t s were t o l d t o produce the e x p e r i m e n t a l u t t e r a n c e s at t h e i r f a s t e s t s p e a k i n g  rate.  Assuming t h a t e x p e r i m e n t a l u t t e r a n c e s were i n d e e d produced at a " f a s t e s t " r a t e o f speech, one might f u r t h e r assume t h a t segmental and c l u s t e r l e n g t h w o u l d d e c r e a s e ; however, t h i s i s not the c a s e , as can be seen i n Tables  3 and  p l a n a t i o n f o r t h i s c o u l d be t h a t o n l y v o w e l s ,  8.  One  ex-  resonants  and  perhaps pauses make a d i f f e r e n c e to r a t e , w h i l e stops  and  f r i c a t i v e s are o n l y s l i g h t l y a f f e c t e d , i f at a l l .  In addi-  t i o n , a possible explanation for this subjectively  faster  r a t e o f speech c o u l d be the change i n d u r a t i o n o f the h e s i t a t i o n pause and the r e l a t i o n o f semantic  c o n t e n t to p a u s a l  time. As G o l d m a n - E i s l e r  (1968) r e p o r t s , v a r i a t i o n s  i n the  o v e r a l l r a t e o f speech or an i n c r e a s e i n r a t e were found to be v a r i a t i o n s i n the amount o f p a u s i n g .  She  concludes  r a t e o f speech based s o l e l y on a r t i c u l a t o r y a c t i v i t y relatively  remained  invariant.  Goldman-Eisler  (1968) a l s o observes  i n r e l a t i o n to semantic meaning, p a u s a l time was content.  that  She  content.  trends i n pausal  time  When s u b j e c t s i n t e r p r e t e d  t w i c e as g r e a t as when they d e s c r i b e d  examined t h i s phenomenon w i t h r e s p e c t t o degrees  69  of s p o n t a n e i t y i n speech.  Where semantic  c o n t e n t becomes  l e s s and l e s s a f a c t o r i n speech, as i n r e p e t i t i o n o f the same u t t e r a n c e , she found t h a t t h e r e was  a decline i n pausal  time a f t e r the f i r s t r e p e t i t i o n and a f u r t h e r d e c r e a s e i n subsequent r e p e t i t i o n s . C o n s i d e r i n g these i n t e r p r e t a t i o n s , one would not assume t h a t c l u s t e r l e n g t h would d e c r e a s e w i t h an i n c r e a s e i n . r a t e but would remain a p p r o x i m a t e l y est  d u r a t i o n i n the l a s t  semantic  content  the same, a t t a i n i n g i t s s h o r t -  ( i . e . , f i f t e e n t h ) r e p e t i t i o n where  i s most f a m i l i a r .  General r e s u l t s can be grouped f o r d i s c u s s i o n p u r p o s e s : The  l o n g e s t s i b i l a n t s are those b e f o r e the v e l a r /k/,  while  the l o n g e s t s t o p consonant i s the b i l a b i a l /p/ and the s h o r t est  the a l v e o l a r ft/.  In the c o n t r o l group d a t a , the  stop  consonant xvas c o n s i d e r e d to determine the l e n g t h of the cluster.  H y p o t h e s i z i n g t h a t such a c o n s t r a i n t h o l d s f o r the  experimental  group d a t a , one might expect  the c o r r e c t e d /sp/-  c l u s t e r s to be the l o n g e s t and the c o r r e c t e d / s t / - c l u s t e r s be the s h o r t e s t .  The  r e s u l t s presented  i n Table  9  to  support  such an h y p o t h e s i s . A p o s s i b l e p h y s i o l o g i c a l e x p l a n a t i o n f o r the f i n d i n g t h a t /sp/ and /sk/ are l o n g e r i n d u r a t i o n than / s t / would be the former i n v o l v e slower moving a r t i c u l a t o r y  that  musculature  (e.g., l i p s and body of the tongue) f o r the stop p r o d u c t i o n , w h i l e both / s / and / t / " i n v o l v e f a s t e r moving, more h i g h l y i n n e r v a t e d tongue t i p m u s c u l a t u r e .  Furthermore, / t / . i s  homorganic  70 w i t h / s / ( i . e . , p l a c e of a r t i c u l a t i o n i s the same, o n l y the manner d i f f e r s ) , whereas the h e t e r o r g a n i c c l u s t e r s /sp/ /sk/ r e q u i r e s e v e r a l d i f f e r e n t muscles i n o r d e r to the a r t i c u l a t o r y g e s t u r e s .  and  complete  These d i f f e r e n t movements s h o u l d  tend ( l o g i c a l l y ) to make p r o d u c t i o n s l o w e r f o r /sp/ and  /sk/  than f o r / s t / . Haggard (1973) a l s o d i s c u s s e s a b b r e v i a t i o n i n c e r t a i n homorganic c l u s t e r s :  He r e p o r t s v a r i e d  individual  d i f f e r e n c e s and supposes t h a t d u r a t i o n s can be c o n t r o l l e d o r a l pressure  by  feedback.  Perhaps the most i n t r i g u i n g f i n d i n g of the p r e s e n t i n v e s t i g a t i o n i s t h a t the elements  of an e r r o r c l u s t e r are a l -  ways l o n g e r than those o f the r e p e t i t i o n , or c o r r e c t i o n p r o duction.  I t i s o f i n t e r e s t t o note the p o s s i b l e e f f e c t s o f  s t r e s s and f o l l o w i n g vowel environment on c l u s t e r d u r a t i o n . Of the t h i r t y - s i x t e s t words embedded i n the t h r e e " t o n g u e - t w i s t e r s " , a l l but two had p r i m a r y s t r e s s on the s y l l a b l e c o n t a i n i n g the c l u s t e r .  Word s t r e s s was  first  therefore  not c o n s i d e r e d to be a major f a c t o r i n determining, c l u s t e r length..  S i m i l a r l y , the f o l l o w i n g vowel environment  was  a n a l y z e d to determine whether r e p e t i t i o n e r r o r s o c c u r r e d more f r e q u e n t l y b e f o r e some vowels and not o t h e r s . t i o n e r r o r s produced b e f o r e the vowel / a e / ,  Of 118  repeti-  by the s i x s u b j e c t s , 39 e r r o r s o c c u r r e d 29 b e f o r e / 1 /, 24 b e f o r e / a / , 9 b e f o r e  /e/, 5 b e f o r e /oo/, 5 b e f o r e / i /, 4 b e f o r e /o/, and 3 b e f o r e •/eL /. • • More r e p e t i t i o n e r r o r s o c c u r r e d b e f o r e the vowels /es/, l\l  and / a / than b e f o r e the o t h e r s .  S i n c e d a t a were not  a n a l y z e d to take f o l l o w i n g vowels i n t o a c c o u n t , no e x p l a n a t i o n  71  as to t h e i r s i g n i f i c a n c e can be o f f e r e d a t t h i s t i m e . import of these r e s u l t s are the t o p i c o f the next 5.3  The  section.  Theoretical Considerations R e s u l t s from the e x p e r i m e n t a l group d a t a s t r o n g l y sug-  gest t h a t d u r a t i o n of a segment or c l u s t e r a l r e a d y produced can a f f e c t subsequent a r t i c u l a t i o n s .  I t seems t h a t e x c e s s i v e  d u r a t i o n of the c l u s t e r as a whole or of e i t h e r o f i t s component p a r t s may  v i o l a t e some s o r t of t i m i n g c o n s t r a i n t on  the system i n the p r o d u c t i o n of a g i v e n u t t e r a n c e ; t h i s  viola-  t i o n causes the p r o d u c t i o n to be h a l t e d i n mid-word, a r e c a l i b r a t i o n to be e f f e c t e d , and a c o r r e c t i o n to be produced. I f , however, an e r r o r i s made w i t h r e s p e c t to the phone t i c form.of  the u t t e r a n c e  (such as a s u b s t i t u t i o n  the t i m i n g c o n s t r a i n t h y p o t h e s i z e d above may  error),  not be  and the u t t e r a n c e would not have to be r e p e a t e d .  violated,  At  present  i t i s not known whether a d d i t i o n or o m i s s i o n e r r o r s v i o l a t e such a t i m i n g c o n s t r a i n t i n words, o r i f o t h e r segments w i t h i n words l e n g t h e n or s h o r t e n to make room f o r an e x t r a element or to f i l l  up an empty space.  I f such a view i s t e n a b l e , the  h e s i t a t i o n e r r o r s (where an i n t r a - w o r d pause or p r o l o n g a t i o n of a segment o c c u r s ) can be c o n s i d e r e d to be a s t e p  earlier  than a r e p e t i t i o n e r r o r ; i . e . , w i t h i n c e r t a i n l i m i t s ,  seg-  mental p r o l o n g a t i o n or pause i n s e r t i o n w i l l be enough f o r the system to r e c a l i b r a t e , but i f such r e c a l i b r a t i o n does not take p l a c e q u i c k l y enough, then p r o d u c t i o n i s c o m p l e t e l y  72  h a l t e d , w i t h the u t t e r a n c e b e i n g r e p r o d u c e d , has been termed here a r e p e t i t i o n  y i e l d i n g what  error.  C o n s i d e r a t i o n s o l e l y o f the r e p e t i t i o n e r r o r s does n o t a l l o w f o r d e t e r m i n a t i o n o f whether (a) a d e l a y i n p r o d u c t i o n o f t h e n e x t phoneme caused t h e r e p e t i t i o n , (b) t h e r e p e t i t i o n i s a c o r r e c t i o n o f an e x c e s s i v e l y l o n g segment, o r (c) t h e r e p e t i t i o n i s a c o r r e c t i o n o f an e x c e s s i v e l y l o n g c l u s t e r uttered.  A combination  o f ( a ) , (b) and (c) i s a l i k e l y  just  solu-  t i o n ; i . e . , e x c e s s i v e l y l o n g segments i n a c l u s t e r a r e produced which causes a d e l a y i n p r o d u c t i o n o f t h e next phoneme, and the second p r o d u c t i o n i n a r e p e t i t i o n e r r o r i s a c o r r e c t i o n o f the t i m i n g v i o l a t i o n .  I n s u p p o r t o f t h i s s o l u t i o n , l e t us  again consider h e s i t a t i o n e r r o r s : no r e p e t i t i o n o c c u r s  As mentioned p r e v i o u s l y ,  i n such e r r o r s (perhaps) because (a) the  d u r a t i o n o f t h e h e s i t a t i o n i s n o t l o n g enough t o v i o l a t e a t i m i n g c o n s t r a i n t , and thus  (b) t h e phoneme t r a n s i t i o n s have  not been l o s t so t h a t p r o d u c t i o n o f t h e word can be c o n t i n u e d . T h i s suggests  t h a t when a r e p e t i t i o n takes p l a c e , i t i s due t o  e x c e s s i v e d u r a t i o n which causes a d e l a y v i o l a t i n g a t i m i n g c o n - , s t r a i n t and r e s u l t s i n l o s s o f phoneme t r a n s i t i o n s .  Conse-  q u e n t l y , t h e u t t e r a n c e cannot be c o n t i n u e d , and a c o r r e c t i o n o f the e x c e s s i v e d u r a t i o n o f t h e f i r s t p r o d u c t i o n i s o r d e r e d . I f such a n o t i o n i s adopted, then how might t h e system d e t e r mine t h a t a t i m i n g c o n s t r a i n t has been v i o l a t e d ' a n d a c o r r e c t i o n c a l l e d for?  73 In o r d e r t o a c c o m p l i s h c o r r e c t i o n o f an element p r e v i o u s l y u t t e r e d , the system must f i r s t was  know t h a t the element  i n c o r r e c t and what the t a r g e t s h o u l d have been; i . e . ,  feedback must be p r e s e n t i n o r d e r f o r the system t o r e c o g n i z e the  d u r a t i o n e r r o r , and comparison o f o u t p u t w i t h the o r i g i -  n a l l y p l a n n e d t a r g e t element must o c c u r i n o r d e r f o r a c o r r e c t i o n t o be e x e c u t e d . The " a n a l y s i s - b y - s y n t h e s i s " model o f speech p e r c e p t i o n and p r o d u c t i o n ( c f . B e l l et a l . , 1961)  i n c o r p o r a t e s a feed-  back method o f speech spectrum a n a l y s i s by w h i c h  correction  of an element p r e v i o u s l y u t t e r e d c o u l d be a c c o m p l i s h e d .  In  terms o f t h i s model, the "spectrum g e n e r a t o r " produces o u t p u t comparable  to s t o r e d speech d a t a ( i . e . , the f i r s t p r o d u c t i o n  o f the u t t e r a n c e ) .  The "comparator" t h e n computes the d i f f e r -  ence between the i n p u t speech s p e c t r a i t has r e c e i v e d v i a a feedback l o o p and the o r i g i n a l t a r g e t u t t e r a n c e j u s t g e n e r a t e d . T r i a l s p e c t r a are s y n t h e s i z e d by the " s t r a t e g y component" u n t i l minimum e r r o r i s o b t a i n e d i n matching and i n t h i s  case  a c o r r e c t i o n of a previous e r r o r utterance i s generated. On the p h y s i o l o g i c a l l e v e l , feedback can o c c u r v i a the a c o u s t i c and/or p r o p r i o c e p t i v e channels (as d i s c u s s e d i n Sect i o n s 1.31 the  and 1.3.2), i . e . , v i a bone and a i r c o n d u c t i o n and/or  gamma motor system.  In the p r e s e n t s t u d y t h e r e i s no  way  to determine i f b o t h channels are i n use at a l l t i m e s , or i f t h e r e i s i n t e r m i t t e n t m o n i t o r i n g by one o r b o t h channels duri n g speech  (as suggested e a r l i e r ) .  One  argument f o r i n t e r -  m i t t e n t feedback d u r i n g speech i s t h a t o m i s s i o n and  addition  74  e r r o r s are u s u a l l y not c o r r e c t e d .  One may  speculate that  such e r r o r s do not v i o l a t e a t i m i n g c o n s t r a i n t p l a c e d on the word, but i t may be more l i k e l y t h a t such e r r o r s have not been "caught" by the system due to i n t e r m i t t e n t m o n i t o r i n g .  In any  c a s e , the s p e a k e r / h e a r e r r e c e i v e s feedback, and some comparison w i t h the o r i g i n a l t a r g e t must take p l a c e -- f a c t s w h i c h models o f speech p r o d u c t i o n (and p e r c e p t i o n ) s h o u l d account f o r . The n o t i o n s d i s c u s s e d thus f a r may  be viewed i n l i g h t  o f F a i r b a n k s ' s (1954) i n t e r p r e t a t i o n o f the speech p r o d u c t i o n system as a s e r v o s y s t e m .  He s u g g e s t e d t h a t t h e r e i s c o n t i n u -  ous m o n i t o r i n g v i a the a c o u s t i c mode, by w h i c h we compare o u t p u t t o i n p u t and t h e r e b y m a n i p u l a t e p r o d u c t i o n .  Monitoring  s o l e l y by means o f the a u d i t o r y channel i s most u n l i k e l y , s i n c e an a d v e n t i t i o u s l y deafened p e r s o n does n o t l o s e h i s speech i m m e d i a t e l y a f t e r an i n j u r y  (as n o t e d i n S e c t i o n 1.62) ;  perhaps such an i n d i v i d u a l can r e l y on h i s p r o p r i o c e p t i v e back from the a r t i c u l a t o r s t o supplement b a r e l y auditory  feed-  discernible  signals.  For the normal h e a r i n g p e r s o n , Abbs (19 73) p r o p o s e d a " v a r i a b l e " ser>/:osystem  ( c f . S e c t i o n 1.63), a model w h i c h  c l o s e l y a c q u a i n t s p r o p r i o c e p t i v e feedback and i n p u t / o u t p u t comparisons. i t employs  T h i s speech p r o d u c t i o n system i s e f f i c i e n t ,  since  feedback depending on i t s r e q u i r e m e n t s , v i a the  gamma o r s p i n d l e motor system.  In order to consider which  system might be i n o p e r a t i o n , l e t us s p e c u l a t e how e r r o r s might v i o l a t e t i m i n g  constraints.  repetition  75  The v i o l a t i o n o f a t i m i n g c o n s t r a i n t c o u l d be due t o a " l a p s e " i n c o n t i n u o u s a u d i t o r y feedback because o f a f a s t e r r a t e o f speech; i . e . , the a u d i t o r y m o n i t o r i n g "comparator") l a g b e h i n d p r o d u c t i o n lengthening  system  (and  t o the e x t e n t t h a t a  o f segments o c c u r s w h i c h , i n the case o f r e p e t i t i o n  e r r o r s , v i o l a t e s a timing constraint.  Perhaps f o r t h i s r e a s o n  these e r r o r s c l o s e l y resemble the r e p e t i t i o n e r r o r s produced under the i n f l u e n c e o f d e l a y e d  a u d i t o r y f e e d b a c k , where a  delay r e s u l t s i n such a " l a p s e " and a r e p e t i t i o n i s produced (cf. Fairbanks  § Guttman, 1958; Lee, 1951).  I f such a l a p s e  does o c c u r , then r e p e t i t i o n e r r o r s are n o t j u s t a p r o d u c t i o n problem, but a l s o a p e r c e p t i o n problem.  In r e l a t i n g  this  n o t i o n o f a u d i t o r y feedback's l a g g i n g speech p r o d u c t i o n the " a n a l y s i s - b y - s y n t h e s i s " model, we might s p e c u l a t e  to  that i t  i s the "comparator", i n computing t h e d i f f e r e n c e between i n p u t and o u t p u t , which has caused the d e l a y , and a . r e c a l i b r a t i o n i s n e c e s s a r y f o r i t t o c a t c h up to p r o d u c t i o n .  The  delay:  thus v i o l a t e s a t i m i n g c o n s t r a i n t here t o o , and a c o r r e c t e d u t t e r a n c e must be produced. To account f o r the f a c t t h a t not a l l speech e r r o r s a r e c o r r e c t e d , one may  speculate  o n l y g e n e r a l sound p a t t e r n s  t h a t a u d i t o r y feedback m o n i t o r s and i n t o n a t i o n , rhythm and s t r e s s  p a t t e r n s , w h i l e p r o p r i o c e p t i v e feedback m o n i t o r s i n t e r m i t t e n t l y for phonetic  deviancies.  In accordance w i t h Abbs (1973) t h i s  i n t e r m i t t e n t p r o p r i o c e p t i v e feedback concerns the gamma o r s p i n d l e motor system, w h i c h  (1) m a i n t a i n s  length or r a t e o f  76  change o f l e n g t h o f a m u s c l e , (2) i n i t i a t e s  contraction,  (3) p r o v i d e s damping movements to p r e v e n t o v e r s h o o t , and (4) supplements  a u d i t o r y feedback when n e c e s s a r y .  There i s a r e a s o n a b l e b a s i s f o r s u p p o s i n g t h a t t h e gamma motor system i s o p e r a t i o n a l w i t h r e s p e c t t o p h o n e t i c a l l y viant repetition errors  (such as those o b s e r v e d i n t h i s  destudy).  I f we c o n s i d e r t h e s h o r t e s t pause between r e p e t i t i o n s o b s e r v e d , here a p p r o x i m a t e l y 20 ms,  and the " t u r n around t i m e " or d e l a y  f o r o p e r a t i o n o f the s p i n d l e system, c a . 20-80 ms, we  find  that  the two f i g u r e s o v e r l a p , and the i n t e r p r e t a t i o n i s not c o n t r a dicted. A l l t o l d , a model o f speech p r o d u c t i o n must account f o r normal u t t e r a n c e s , as w e l l as f o r speech e r r o r s .  Moreover,  i t must a l l o w f o r a p p r o p r i a t e types o f feedback and be an e f f i c i e n t system f o r r e l a t i n g speech p r o d u c t i o n to p e r c e p t i o n . The v a r i a b l e s e r v o m o n i t o r system o u t l i n e d above i n c o r p o r a t e s b o t h c o n t i n u o u s a u d i t o r y feedback and i n t e r m i t t e n t p r o p r i o c e p t i v e feedback, which are used i n p e r c e i v i n g i n p u t and u s i n g it  to m a n i p u l a t e o u t p u t .  T h i s system a l s o p r o v i d e s a p l a u s i b l e  account o f the speech e r r o r s and of t h e i r p r o d u c t i o n as desc r i b e d i n t h i s study.  T h e o r e t i c a l l y , the system advocated  here p r o v i d e s an e f f i c i e n t means f o r p r o d u c i n g , m o n i t o r i n g and c o r r e c t i n g speech p r o d u c t i o n . 5.4  L i m i t a t i o n s of the P r e s e n t Study One c f the purposes o f t h i s i n v e s t i g a t i o n w a s t o examine :  speech e r r o r s under c o n d i t i o n s of r a p i d r e p e t i t i o n o f t h r e e  77  "tongue-twisters".  I t was h y p o t h e s i z e d t h a t e r r o r s o b t a i n e d  u s i n g a f a s t e r than normal s p e a k i n g r a t e might be due t o a t l e a s t the f o l l o w i n g :  (1) The words were s i m i l a r i n p h o n o l o g i c a l  form and p h o n e t i c content  ( i . e . , t w e l v e o c c u r r e n c e s each o f  / s p / , / s t / and / s k / i n w o r d - i n i t i a l p o s i t i o n ) , and (2) t h e f a s t e r r a t e o f speech w h i c h , when combined w i t h ( 1 ) , r e s u l t s in error productions.  These i n v o l v e v a r i a b l e s such as psycho-  l o g i c a l and p h y s i c a l s t r e s s and f a t i g u e which were not cont r o l l e d f o r -- i f i n d e e d they can be c o n t r o l l e d f o r -- i n this  study. The  f o l l o w i n g l i m i t a t i o n s a p p l y t o any i n t e r p r e t a t i o n  of the d a t a : (1)  Generation, o f speech e r r o r s may not produce t h e same type  o f e r r o r s as. those produced  i n spontaneous speech.  They may  be due t o memory l i m i t a t i o n s , w h i c h , when combined w i t h speaki n g r a t e , p u t undue s t r e s s on the s p e a k e r , who may then p r o duce " u n n a t u r a l " e r r o r s .  As s u c h , t h e e r r o r s d e s c r i b e d may  be a r t i f a c t s o f the e x p e r i m e n t a l method employed. (2)  Words w i t h i n i t i a l  f r i c a t i v e p l u s stop consonant  clusters  were not c o n t r o l l e d f o r number o f s y l l a b l e s , word c l a s s , s t r e s s placement o r p l a c e i n s e n t e n c e . The  above were c o n s i d e r e d to be the major l i m i t a t i o n s o f t h i s  s t u d y , and due c o n s i d e r a t i o n f o r the c o n t r o l o f such s h o u l d be g i v e n t o f u t u r e r e s e a r c h i n t h i s 5.5  variables  area.  Summary and C o n c l u s i o n s The p r e s e n t study f i r s t examined the means by w h i c h t h e  g e n e r a t i o n and the c l a s s i f i c a t i o n o f speech e r r o r s c o u l d be  78 accomplished.  I t was  found t h a t a " t o n g u e - t w i s t e r " , which  c o n t a i n e d many o c c u r r e n c e s  of words with' s i m i l a r p h o n o l o g i c a l  form ( i . e . , w i t h w o r d - i n i t i a l / s p / , / s t / and / s k /  clusters),  produced at a s u b j e c t ' s f a s t e s t s p e a k i n g  repeated  many times would generate  r a t e and  the most speech e r r o r s .  These e r r o r s  were then c l a s s i f i e d a c c o r d i n g t o c a t e g o r i e s combined from the l i t e r a t u r e on speech e r r o r s and on DAF  research.  cent o f a l l e r r o r s produced by s u b j e c t s i n t h i s were o f the r e p e t i t i o n t y p e .  F i f t y perr investigation  C o n s i d e r a t i o n o f the p o s s i b l e  causes o f the e r r o r s encountered  l e d to the d e t a i l e d examina-  t i o n o f the w o r d - i n i t i a l c l u s t e r and component segment durations. The general (1)  The  e x p e r i m e n t a l i n v e s t i g a t i o n y i e l d e d the  following  results: stop consonant i n a g i v e n c l u s t e r seems to  determine  the o v e r a l l c l u s t e r d u r a t i o n , s i n c e the d u r a t i o n o f / s / i r r e s p e c t i v e o f c o n t e x t remains f a i r l y (2)  The  constant.  c l u s t e r s /sp/ and /sk/ are l o n g e r i n d u r a t i o n than  / s t / , w h i c h r.iay be a t t r i b u t a b l e t o the s l o w e r moving a r t i c u l a t o r y musculature  a s s o c i a t e d w i t h /p/ and /k/ p r o d u c t i o n com-  pared w i t h the f a s t e r moving, more h i g h l y i n n e r v a t e d tongue t i p musculature (3)  The  i n v o l v e d i n t h e . p r o d u c t i o n o f / s / and  ft/.  c l u s t e r segments i n the e r r o r p r o d u c t i o n s were con-  s i s t e n t l y l o n g e r i n d u r a t i o n than i n the second, o r c o r r e c t e d , p r o d u c t i o n (which approximated for  more c l o s e l y the v a l u e s  obtained  the c o n t r o l group d a t a t h a n might have been o t h e r w i s e  p e c t e d due  to m e t h o d o l o g i c a l d i f f e r e n c e s ) .  :  ex-  79  In l i g h t o f t h e above r e s u l t s , i t was s p e c u l a t e d t h a t the e x c e s s i v e d u r a t i o n o f the c l u s t e r  ( o r o f i t s component  p a r t s ) v i o l a t e d a t i m i n g c o n s t r a i n t on the p r o d u c t i o n o f an u t t e r a n c e , whereupon phoneme t r a n s i t i o n s a r e l o s t t o t h e s y s tem,  f o l l o w i n g which a r e c a l i b r a t i o n must t a k e p l a c e and a  c o r r e c t i o n produced.  From such c o n s i d e r a t i o n s i t was i n f e r r e d  t h a t feedback must be p r e s e n t i n o r d e r f o r the system t o r e c o g n i z e the d u r a t i o n e r r o r , t o compare i t w i t h p l a n n e d o u t p u t , and f i n a l l y t o execute a c o r r e c t i o n . On the p h y s i o l o g i c a l l e v e l , feedback was c o n s i d e r e d t o be b o t h c o n t i n u o u s ( a u d i t o r y channel) and i n t e r m i t t e n t  (pro-  p r i o c e p t i v e c h a n n e l , i n v o l v i n g t h e gamma motor s y s t e m ) ; t h e l a t t e r may supplement  a u d i t o r y feedback and scan f o r d e v i a n t  p h o n e t i c e l e m e n t s , w h i l e the former m o n i t o r s g e n e r a l sound p a t t e r n s , p a r t i c u l a r l y suprasegmental p a t t e r n s . As a r e s u l t o f t h e s e c o n s i d e r a t i o n s , i t was h y p o t h e s i z e d t h a t a t i m i n g c o n s t r a i n t i s imposed by t h e system.  When t h i s  c o n s t r a i n t i s v i o l a t e d , perhaps due t o a d e l a y i n a u d i t o r y feedback p r o c e s s i n g o c c a s i o n e d by the f a s t e r than normal i n g r a t e , a speech e r r o r o c c u r s .  speak-  Because o f t h i s , r e p e t i t i o n  e r r o r s were r e g a r d e d as much a p e r c e p t i o n problem as a product i o n problem.  REFERENCES Abbs, J.H.  1973.  The influence of the gamma motor system  on jaw movements during speech: A t h e o r e t i c a l framework and some preliminary observations. Journal of Speech and Hearing Research 16. 175-200. Alston, W., R.W. Angel, F.S. Fink, and W.W. Hofmann. 1967. Motor a c t i v i t y following the s i l e n t period i n human muscle. Journal of Physiology 190. 189-202. [Cited i n Abbs, 1973.] B e l l , C.G.,  H. F u j i s a k i , J.M.  Heinz, K.N.  Stevens,  and  A.S. House. 1961. Reduction of speech spectra by analysis-by-synthesis techniques. Journal of the Acoustical Society of America 33. 1725-1736. Bernstein,. N.A. Movements. 1973.]  1967. The Coordination and Regulation of Oxford: Pergamon Press. [Cited i n Ohala,  Berry, M., and J. Eisenson. 1956. Speech Disorders: P r i n c i ples and Practices of Therapy. New York: AppletonCentury-Crofts. Black, J.W.  1951.  The e f f e c t of delayed side-tone upon  vocal rate and i n t e n s i t y . Disorders 16. 56-60. Boomer, D.S.,  and J.D.M. Laver.  Journal of Speech and 1968.  Hearing  S l i p s of the tongue.  B r i t i s h Journal of Disorders of Communication 3. Borden, G.J..and T. Gay.  1975.  1.12.  Durations of a r t i c u l a t o r  movements for /s/.-stop. c l u s t e r s .  Haskins Laboratories  Status Report on Speech Research SR-44. 147-160. Bowman, J.P.  1971.  the Tongue. Campbell, E.J.M.  S p r i n g f i e l d , 111.: 1968.  duction i n Man, . New  The Muscle Spindle and Neural Control of Charles C Thomas.  The r e s p i r a t o r y muscles.  ed. by A. Bouhuys, .135-140.  York Academy of Sciences.  80  Sound ProNew  York:  [Cited i n Abbs, 1973.J  81 Chase, R.A.  1958.  E f f e c t of delayed auditory feedback on  the r e p e t i t i o n of speech sounds.  Journal of Speech and  Hearing Disorders 23. 583-590. Euler, C. von.  1966.  Proprioceptive control i n r e s p i r a t i o n .  Muscular Afferents and Motor Control, ed. by R. Granit, 197-208.  New York: Wiley.  [Cited i n Abbs, 1973.]  Fairbanks, G. 1954. Systematic research i n experimental phonetics: 1. A theory of the speech mechanism as a servosystem. Journal of Speech and Hearing Disorders 19. 133-139. Fairbanks, G.  1960.  edition.  New  Voice and A r t i c u l a t i o n Drillbook, 2nd  York: Harper &  Row.  Fairbanks, G., and N. Guttman. 1958. E f f e c t s of delayed auditory feedback upon a r t i c u l a t i o n . Journal of Speech and Hearing Research 1. 12-22. Freud, S. 1924. Zur Psychopathologie des Alltaglebens, 10th edition. L e i p z i g : Internationaler Psychoanalytischer Verlag. [Cited i n Fromkin, 1971.] Fromkin, V.A.  1968.  Speculations on performance models.  Journal of L i n g u i s t i c s 4. 47-68. Fromkin, V.A.  1971.  utterances. Fromkin, V.A; ican 229  The non-anomalous nature of anomalous  Language 47. -27-52.  1973.  S l i p s of the tongue.  (6). 110-117.  Goldman-Eisler,  F.  1968.  Spontaneous Speech. Grinker, R.R., 111.: Haggard, M.  S c i e n t i f i c Amer-  and P.C.  Psycholinguistics: Experiments i n London: Academic Press.  Bucy.  1949.  Neurology.  Springfield,  Charles C Thomas. 1973.  Abbreviation of consonants i n English pre-  and post-vocalic c l u s t e r s .  Journal of Phonetics 1,  9-24.  82 Kardy, J.C.  1970.  underlying  Development  of neuromuscular systems  speech production.  Speech.and the Dentofacial  Complex: The State of the Art (ASHA Reports No. 5), 49-68. Washington, D.C.:  American Speech and Hearing Association.  Johnston, T.B., and J . W h i l l i s (Eds.). 1954. Gray's Anatomy Descriptive and Applied, 31st e d i t i o n . London: Longmans, Green and Co. Kent, R.D., and K.L. Moll. 1975. A r t i c u l a t o r y timing i n selected consonant sequences. Brain and Language 2. 304-323. Konigsmark, B.'W. 1970. Neuroanatomy of speech. Speech and the Dentofacial Complex: The State of the Art (ASHA Reports No. 5), 3-19. Washington, D.C.: American Speech and Hearing Association. Kozhevnikov, V.A., and L.A. Chistovich. 1965. Speech: A r t i c u l a t i o n and Perception. [Joint Publications Research Service, No. 30,543,] Washington, D.C.: U.S. Department of Commerce. Lee, B.S. 1950. E f f e c t s of delayed speech feedback. Journal of the Acoustical Society of America 22. 824-826. Lee, B.S.  1951.  A r t i f i c i a l stutter.  Journal of Speech and  Hearing Disorders 16. 53-55. Lehiste, I.  1971.  Temporal organization of spoken language.  Form & Substance, ed. by L.L. Hammerich, R. Jakobson, and E. Zwirner, 159-169.  Copenhagen: Akademisk Forlag.  Lehiste, I., and G.E. Peterson.  1959.  Vowel amplitude and  phonemic stress i n American English.  Journal of the  Acoustical Society of America 31. 428-435. Lenneberg, E.H. 1967. New York: Wiley.  B i o l o g i c a l Foundations of Language.  MacKay, D.G. 1970. Spoonerisms: The structure of error i n the s e r i a l ordering of speech. Neuropsychologia 8. 323-350.  83 MactJeilage, P.F. •speech.  1970.  Motor c o n t r o l o f s e r i a l o r d e r i n g o f ".  P s y c h o l o g i c a l Review 77.  M a c N e i l a g e , P.F.  1972.  182-196.  Speech p h y s i o l o g y -  Speech and  C o r t i c a l F u n c t i o n i n g , ed. by J . G i l b e r t , 1-72.  New  York:  Academic P r e s s . Meringer,  K.  1908.  Aus  dem  Leben der Sprache.  Berlin.  [ C i t e d i n F r o m k i n , 1971.] Meringer,  K.,  and K. Mayer.  1895.  V e r s p r e c h e n und  E i n e p s y c h o l o g i s c h l i n g u i s t i s c h e Studie..  Verlesen,  Vienna.  [ C i t e d i n F r o m k i n , 1971.] Merton, P.A. 1953. S p e c u l a t i o n s on the s e r v o - c o n t r o l o f movement. The S p i n a l Cord, ed. by G.E.W. Wolstenholme, 247-255. London: C h u r c h i l l . [ C i t e d i n Abbs, 1973.] M o r t i m e r , E.M., and K. A k e r t . 1961. C o r t i c a l c o n t r o l and r e p r e s e n t a t i o n o f f u s i f o r m neurons. A m e r i c a n J o u r n a l o f P h y s i c a l M e d i c i n e 48. 228-248. [ C i t e d i n Abbs, 1973.] N e t t e r , F.H. 1972. The CIBA C o l l e c t i o n o f M e d i c a l I l l u s t r a t i o n s , Volume 1: Nervous System. Summit, N.J.: CIBA P h a r m a c e u t i c a l Co. Nooteboom, S.G.  1969.  The  tongue s l i p s i n t o p a t t e r n s .  Nomen: Leyden S t u d i e s i n L i n g u i s t i c s and P h o n e t i c s , by A.G. Ohala, J . J . speech.  S c i a r o n e e t a l . , 114-132. 1970.  The Hague: Mouton.  o f the c o n t r o l and p r o d u c t i o n o f  Working Papers i n P h o n e t i c s , No.  Los A n g e l e s : Ohala, J . J .  Aspects  1973.  ed.  15.  U n i v e r s i t y of C a l i f o r n i a . The  t e m p o r a l r e g u l a t i o n o f speech.  C o l l e c t i o n o f Papers P r e s e n t e d a t Symposium on A u d i t o r y A n a l y s i s and P e r c e p t i o n o f Speech ( L e n i n g r a d , August 21-24), ed. by H. F u j i s a k i , 516-538. Tokyo: U n i v e r s i t y o f Tokyo. P e n f i e l d , W., o f Man.  and T. Rasmussen. New  York:  1950.  Macmillan.  The  Cerebral  Cortex  84  Perifield, W., and L. Roberts. Mechanisms .  1959. Speech and Brain-  Princeton, N.J.: Princeton University Press.  Ruch, T.C., H.D. Patton, J.W. Woodbury, and A.L. Towe. 1967. Neurophysiology. Philadelphia: W.B. Saunders. [Cited i n Abbs, 1973.] Sataloff, J . 1966. Hearing Loss.  Philadelphia: L i p p i n c o t t .  Schwartz, M.F. 1970. Duration of /s/ i n /s/-plosive blends. • Journal of the Acoustical Society of America 47. 11431144.  Sears, T.A., and J . Newsome Davis. 1968. The control of respiratory muscles during v o l u n t a s breathing. Sound Production i n Man, ed. by A. Bouhuys, 183-190. New York: New York Academy of Sciences. [Cited i n Abbs, 1973.] Smith, J.L.  1969. Fusiform Neuron Block and Voluntary Arm  Movement i n Man.  Unpublished doctoral d i s s e r t a t i o n ,  University of Wisconsin.  [Cited i n Abbs, 1973.]  Smith, T.S. 1973. Review of Bowman (1971). Phonetics 1. 171-179.  Journal of  Stark, L. 1968. Neurological control systems: Studies i n bioengineering. The Hand, 301-410. New York: Plenum. [Cited i n Abbs, 1973.] Stromsta, C. pathways. 34.  1962. Delays associated with c e r t a i n sidetone Journal of the Acoustical Society of America  392-396.  [Cited i n Van Riper, 1971.]  Sturtevant, E.H. 1917. L i n g u i s t i c Change. s i t y of Chicago Press.  Chicago: Univer-  Sturtevant, E.H. 1947. An Introduction to L i n g u i s t i c New Haven: Yale U n i v e r s i t y Press. Van Riper, C. 1971.. The Nature of Stuttering. C l i f f s , N.J.: P r e n t i c e - H a l l .  Science.  Englewood  APPENDIX  A  The f i r s t p a r a g r a p h o f T h e Rainbow Passage'' ( F a i r b a n k s , n  1960,  p. 1 2 7 ) :  "When t h e s u n l i g h t s t r i k e s r a i n d r o p s i n t h e a i r , they a c t l i k e a p r i s m and form a rainbow.  The r a i n b o w i s a  d i v i s i o n o f w h i t e l i g h t i n t o many b e a u t i f u l c o l o r s . t a k e t h e shape o f a l o n g round a r c h , w i t h i t s p a t h  These high  above, and i t s two ends a p p a r e n t l y beyond t h e h o r i z o n . There i s , a c c o r d i n g t o l e g e n d , one end.  a b o i l i n g pot of gold at  P e o p l e l o o k , b u t no one ever f i n d s i t .  When a  man l o o k s f o r something beyond h i s r e a c h , h i s f r i e n d s say he i s l o o k i n g f o r t h e p o t o f g o l d a t t h e end o f t h e rainbow."  85  APPENDIX  B  P a r a g r a p h s w i t h embedded w o r d - i n i t i a l / s C / - c l u s t e r s :  /sp-/:  " I n s c h o o l I had a f r i e n d nicknamed 'Spud', was  t e r r i b l e a t most e v e r y t h i n g .  i n the s c h o o l s p e l l i n g bee, s p e e d i l y and won  /st-/:  One  afternoon  Spud s p e l t  the s c h o o l s p e l l i n g  " I n s c h o o l I a l s o had two f r i e n d s , S t e w a r t , who  One  'spaghetti'  prize."  Stan  and  were always f i g h t i n g w i t h one  day w h i l e i n a f i g h t , Stewart  who  another.  stepped on Stan's  stomach, and he d i e d t h r e e days l a t e r . "  /sk-/:  "Another f r i e n d from my She  s c h o o l days was  Skana.  l i k e d d o i n g a n y t h i n g b e t t e r than g o i n g to s c h o o l .  I n f a c t , Skana s k i p p e d s c h o o l so s k i l l f u l l y t h a t no one knew what happened t o h e r . "  86  APPENDIX  "Tongue-twisters"  /sp-/:  C  w i t h embedded w o r d - i n i t i a l / s C / - c l u s t e r s  "A s p e c t r e o f a s p i r i t e d s p e c t a c l e d 'Spartan'  Spanish  c a l l e d Spinoza a t e the spotted  spiced  s p i n a c h s p o r a d i c a l l y w i t h a spoon b e f o r e i t spoiled."  /st-/:  "The s t a l w a r t s t a l l i o n and t h e statuesque.,£teer were s t a r t l e d by t h e s t o i c a l s t a b l e s t a f f  stealing  sjtagnant stew o f f t h e s t o v e . "  /sk-/:  "Scandinavians  s k i l l f u l l y s k i n and s c a l d s c a l l i o n s ,  s c a l l o p s , scampies and skimpy s c o r p i o n s  until  t h e y a r e s c a r c e l y s c a r l e t , t h e n s c a r f them down."  87  APPENDIX  D  PHONETIC TRANSCRIPTIONS.AND"CODING  The r e p e t i t i o n errors f o r each subject i n this study are l i s t e d according to type (or experimental  group),  phonetic t r a n s c r i p t i o n (using a modified version of the International Phonetic Alphabet), and standard orthographi form of the target utterance. i n i t i a l clusters:  A l l errors involve the word  /sp-/, / s t - / ,  /sk-/. Page  Svibject 1  8  Subject 2  90  Subject 3  91  Subject 4 ..  92  Subject 5  93  Subject 6  94  88  9  SUBJECT  1.  REPETITION  (Total: 18)  ERRORS.  Experimental Group #1:  /sp-/  [s?spinooza]  'Spinoza'  (Phoneme Repetition)  /st-/  [s?stooikJ]  'stoical'  Experimental Group #2:  /sk-/  [sk?sks3mpiz]  'scampies'  [skh?skiIfoli]  'skillfully'  [ skh?skcsmp i z ]  'scampies'  [sk?skiIfoli]  'skillfully'  (Cluster Repetition, with a Pause)  Experimental Group #3:  /sp-/  [spspojadikli]  'sporadically'  (Cluster Repetition, without a Pause)  /st-/  [st stffitJjuesk]  'statuesque'  /sk-/  [skskiIfoli]  'skillfully'  Experimental Group #4:  /sp-/  [spe*?spadid]  'spotted'  [spe?spekt a ]  'spectre'  [sphei?spadid ]  'spotted'  /st-/  [st e?stajtId]  'startled'  /sk-/  [skha?skajlet]  'scarlet'  /st-/  [st aeks?st*t Jjuesk]  'statuesque'  [ stffit?staet J j u e s k ]  'statuesque'  [ s k a j ? s k a j 1 et ]  'scarlet'  [skaem?skajf ]  'scarf'  (/sCV-/ S y l l a b l e Repetition)  Experimental Group #5: (/sCVC-/ S y l l a b l e Repetition)  Experimental Group #6:  h  h  /sk-/  J  h  h  No observations.  (Word Repetition)  89  SUBJECT  2.  REPETITION  ERRORS .  (Total: 28)  Experimental Group #1:  /.sp-/  [s?spekt3kald]  'spectacled'  (Phoneme Repetition)  /st-/  [ s?siaet J j u e s k ]  'statuesque'  /sk-/  [ s?sks i jenz ]  'scallions'  [s?skimp i ]  'skimpy'  [s?skhajlet]  1  scarlet'  [ s?skae 1 aps ]  'scallops'  [s?skimp i ]  'skimpy'  [ s?skae 1 j a n z ]  'scallions'  [ s?skaemp i z ]  'scampies'  Experimental Group #2:  /sp-/  [ s *ph?spoj£edi kl i']  1  (Cluster Repetition., with a Pause)  /sk-/  [skh?skiIfoli]  'skillfully'  [sk?sksl j a n z ]  'scallions'  Experimental Group #3:  /st-/  C S t S t 1 1t Q ]  'stealing'  (Cluster Repetition, without a Pause)  /sk-/  [ sk: s k i n ]  'skin'  Experimental Group #4:  /sp-/  [sp ai?spadid]  'spotted'  (/sCV-/ S y l l a b l e Repetition)  /st-/  [ st se?stst J j u e s k ]  'statuesque'  [stestffi1jan]  'stallion'  [st o?stootkl ]  'stoical'  /sk-/  [sti?skiIfoli]  'skillfully'  /sp-/  [sph i j ? s p ^ i J i d i d ]  'spirited'  [spek ?spekta ]  'spectre'  h  h  h  h  Experimental Group #5: (/sCVC-/ S y l l a b l e Repetition)  h  J  /st-/  [st ooikst ooik J]  'stoical'  /sk-/  [stilf?skiIfoli]  'skillfully'  [ skirnp?skimp i ]  'skimpy'  [skasmp ?skaemp i z ]  'scampies'  [skaent ?sk3empiz]  'scampies'  [skaj?skeusl i ]  'scarcely'  [ spekld?spekt aBkl d ]  'spectacled'  h  h  h  h  h  Experimental Group #6:  sporadically'  /sp-/  h  (Word Repetition)  90  SUBJECT 3.  (Total: 15)  REPETITION ERRORS.  Experimental Group #1:  /sk.-/  (Phoneme Repetition)  [ s?skimph i ]  ' skimpy'  [s?skimp i ]  ' skimpy'  . [s?skasleps]  Experimental Group #2:  /sk-/  (Cluster Repetition, with a Pause) Experimental Group #3:  /sk-/  (Cluster Repetition, without a Pause) Experimental Group #4:  /sk-/  (/sCV-/ S y l l a b l e Repetition) Experimental Group #5:  'scallops'  [s?skhimp i ]  ' skimpy'  [s?skajf ]  1  [ sk ?ska3ndenetv i j a n z ]  ' Scandinavians'  [skh?skbaemp i z ]  'scampies'  [skrhskajf]  'scarf  [sk:ski Ifoli ]  'skillfully'  [ sklu?sk imp i ]  ' skimpy'  [skha?skha-ilet]  'scarlet'  h  h  /st-/  '[ staeg?staet J j u e s k ]  /sk-/  [skojpiz?skslaps]  scarf  ' statuesque'  (/sCVC-/ Syllable. Repetition) Experimental Group #6: (Word Repetition)  ' scallops'  [skhin?skajf]  'scarf  [skhin?skhin]  'skin'  91  SUBJECT  4.  REPET3  (Total: 33)  ERRORS.  Experimental Group #1:  /sp-/  [; s ? s p e k t s k M d ]  'spectacled'  (Phoneme Repetition)  1st-!  i; s ? s t e b l ]  'stable'  ! s?stae 1 jan ]  Experimental Group #2;  /st-/  (Cluster Repetition, with a Pause)  [! s t ? s t e i b l 3 h  'stalwart'  .st ?stooikhal ]  'stoical'  .st ?stffignt ]  'stagnant  ;sth?sthfliQ]  'stealing'  . sk ?skm ]  'skin'  .sk: skimp i ]  1  .sk?skojp i j e n z ]  'scorpions'  .sk:?sktmpi]  'skimpy'  . skh?skasl j e n z ]  'scallions'  h  h  h  h  /sp-/  (Cluster Repetition, without a Pause)  'stable'  !st ?stalweJt]  h  Experimental Group #3:  'stallion'  [. s p : s p h o j s d i k l i ]  skimpy'  'sporadically'  .sp: spadid ]  'spotted'  .sp:spaj?n ]  'Spartan'  h  :  /sk-/  [. s k : h s k i I f o l i ]  'skillfully'  Experimental Group #4:  /sp-/  [. spaTspasm J ]  'Spanish'  (/sCV-/ S y l l a b l e Repetition)  /st-/  [ stae?st ae 1 jen ]  'stallion'  h  .ste?steib]]  'stable'  st3B?staet Jjuesk']  'statuesque'  sti?stoov]  'stove'  stae?staegnt ]  'stagnant'  sta?staIweJt]  'stalwart'  /sk-/  [ ske ?ska31 jenz ]  'scallions'  Experimental Group #5:  /sp-/  [ spad?spijidid]  'spirited'  (/sCVC-/ S y l l a b l e Repetition)  /st-/  [ staegn?sta3t J j u e s k ]  'statuesque'  A  staljeJ?stalweJt]  /sk-/  [ s k i 1?skimpi] skil?skin]  Experimental Group #6: (Word Repetition)  /sk-/  'stalwart' 'skimpy' •skin'  [ skhajfet?skhajlet]  'scarlet  skhuiph9?skimp i ]  'skimpy'  ski 1f?skimpi]  'skimpy'  92  1  SUBJECT 5.  REPETITION  Experimental Group #1: • Experimental Group  #2:  (Total: 11)  ERRORS. No observations. No observations. /sk-/  [sk:ska laps]  'scallops'  Experimental Group #4:  /sp-/  [spA?spadid]  'spotted'  (/sCV-/ S y l l a b l e Repetition)  /st-/  [ s t o o ? s t a 3 1 Jj'uesk]  'statuesque'  /sk-/  [sk ae?skae l a p s ]  'scallops'  [skae?skas!eps]  'scallops  [sk*u?skhin]  'skin'  [ sk aem?ska 1 aps J  'scallops'  [sksel?sk3ndmevi janz ]  'Scandinavians'  [staj?skh jlet]  'scarlet'  Experimental Group #3: (Cluster Repetition, without a Pause)  Experimental Group  #5:  /sk-/  (/sC«'C-/ S y l l a b l e Repetition)  h  h  h  h  a  1  Experimental Group #6:  /sp-/  [spekt a?spekt a ]  'spectre'  (Word Repetition)  /sk-/  [st ejsl iskheusl i ]  'scarcely'  h  h  93  h  J  SUBJECT  6.  REPETITION  (Total: 13)  ERRORS.  Experimental Group #1  No observations.  Experimental Group #2:  /sp-/  (Cluster Repetition, with a Pause) '  [ spVsp i - H d i d ]  'spirited'  [sp ?spekt akaId] r ho n |. sp ?spaemj J  'spectacled'  [sph?spajtn]  'Spartan'  h  h  h  /sk-/  [skh?5kaleps] [sk^?skin]  'Spanish'  ' scallops' •skin'  [skh?skiIfoli]  'skillfully'  /st-/  [ s t : staetJjuesk]  ' statuesque'  Experimental Group #4:  /st-/  [ s t e ? s t a I we- 1 ]  'stalwart'  (/sCV-/ S y l l a b l e  /sk-/  [skhi?skimpi]  'skimpy'  [ska?skaIeps]  'scallops'  [skas?skeel j e n z ]  'scallions'  [ staeg?staegnant ]  'stagnant'  Experimental Group #3: (Cluster Repetition, without a Pause)  Repetition)  Experimental Group #5:  /st-/  1  C/sCVC-/. S y l l a b l e Repetition) Experimental Group #6:  No observations.  94  

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