Timing of upper lip protrusion gestures for the vowel /u/

Timing of upper lip protrusion gestures and accompanying acoustic events was examined for multiple repetitions of word pairs such as “lee coot” and “leaked coot” for three speakers of American English. The duration of the intervocalic consonant string was manipulated by using various combinations of/s,t,k,h,♯/. Pairwise comparisons were made of times of acoustic /i/ offset to acoustic /u/ onset (consonant string duration), protrusion onset to acoustic /u/ onset (onset interval), maximum acceleration to acoustic /u/ onset (acceleration interval), and acoustic /u/ onset to protrusion offset (offset interval). In spite of considerable token‐to‐token and cross‐speaker variation, several general observations were made. There were some consonant‐specific effects, primarily for /s/. The non‐s subset evidenced two modes of behavior. (1) The lip protrusion gesture for /u/ had a relatively invariant duration, but its timing varied with respect to the oral consonant gesture complex: The longer the consonant string, the earlier the lip protrusion gesture, or (2) the protrusion gesture duration correlated positively with consonant duration. The mode 1, which predominated, the slope of the timing relationship between oral and labial gestures differed across subjects. [Work supported by NIDCD.]