Velar/vowel coarticulation in three talkers
Sylvie M. Wodzinski, Stefan A. Frisch
University of South Florida

	The study of speech production provides one source of evidence for 
the mental representations that underlie language (Fromkin, 1971). 
Research in linguistics has discovered a wide range of phonological 
processes where sounds within words are changed depending on their 
context, such as velar fronting (Kenstowicz, 1995). In velar fronting, the 
/k/ and /g/ stop consonants of English are produced with closure in a 
different position depending on the vowel that follows them. This study 
provides an in depth examination of the relationship between the 
articulatory details of speech production and phonological processes such 
as velar fronting.

	The purpose of this study is to conduct a thorough investigation 
of consonant/vowel co-articulation in the case of velar fronting by 
measuring productions of velar stops in the context of a wide range of 
American English vowels. Onset velar stops were measured in both words and 
non-words within a carrier phrase. Measurements were made from ultrasound 
video at the point of closure. Closure location was quantified by the 
angle of elevation from the horizontal axis of the ultrasound probe to the 
center of the velar closure. Frontness of the following vowel was 
quantified using the frequency of the second formant.

	Three subjects were recorded and analyzed. For front vowels, the 
degree of fronting of the velar closure appears to be strongly correlated 
with the frontness of the vowel. For central and back vowels, closure 
location was less variable though an overall effect of vowel frontness can 
still be observed. The correlation between velar closure angle and the 
following vowel F2 was high (Pearson correlation, r>.7) for all three 
subjects for both words and non-words.

	Though there was some grouping of closure location for velars 
before back vowels, overall it appears that closure location for each 
velar/vowel combination is in a distinct location. This suggests that the 
velar fronting 'rule' involves more than a front vs. back specification. 
Possible formulations of velar fronting as either a phonetic 
coarticulatory rule, or as a distributional pattern in an exemplar-based 
phonological grammar, will be presented.