UBC Theses and Dissertations
The Gestural organization of North American English /r/ : a study of timing and magnitude Campbell, Fiona Margaret
The syllable-based allophonic variation in the relative timing and magnitude of two gestures which has been observed for a number of complex segments, including /l/, /w/ and nasal consonants (Sproat and Fujimura, 1993; Browman and Goldstein, 1995; Krakow, 1999; Gick, 2003), provides the generalization that more anterior gestures tend to appear at syllable peripheries. However, because only two gestures are examined it is not clear how to characterize the gestures involved, nor whether timing offsets are categorical or gradient. North American English /r/ is a particularly variable and complex segment with three constrictions - tongue root (TR), tongue tip/blade/body (TB), and lips (Lip), perhaps the reason it has been the subject of numerous studies (Delattre and Freeman, 1968; etc.). That said, technological limitations have hindered the ability of articulatory studies to accurately examine the timing and magnitude of all three gestures of /r/ (Gick and Campbell, 2003). With the object of better understanding the nature and role of timing offsets within phonetics and articulatory phonology, this thesis reports the results of an experiment examining productions of /r/ by nine speakers of Canadian English. The present study uses a novel combination of M-mode ultrasound to measure lingual gestures and Optotrak to measure lip gestures - a significant improvement over previous methods, particularly with respect to temporal resolution (Campbell, Gick, & Namdaran, 2004). Despite variable tongue position/shapes across subjects, cross-subject results show a position-based reduction in gestural magnitude similar to that observed in previous studies (see Krakow, 1999); the Lip and TB gestures were reduced in syllable-final position and the TR gesture was reduced in syllable-initial position. Results also indicate that there is a pattern of front-to-back timing in syllable-initial position, with the Lip occurring before the TB, which occurs before the TR. In syllable-final position the order observed was TR and Lip, followed by TB. These findings are not wholly consistent with any of the theories advanced thus far to explain syllable-based allophonic variation. It is proposed that the relative magnitude of gestures is a better predictor of timing than the relative anteriority of a gesture or an assigned phonological classification.
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