Kris Tjaden
Gary Weismer
Waisman Ctr. and Dept. of Commun. Disorders, 1500 Highland Ave., Univ. of Wisconsin---Madison, Madison, WI 53705
The form of phonetic gestures has been assumed to remain stable across variations in speaking rate. Segmentalization or amount of gestural overlap has been shown to covary with speaking rate. However, the precise relationship between speaking rate and acoustic measures of segmentalization has not been delineated. In the present investigation, speakers produced multiple repetitions of the words ``build,'' ``dill,'' and ``gill'' in carrier phrases at graded, self-selected speaking rates ranging from slow to fast. F2 onset frequency of the vocalic nucleus served as an index of segmentalization and was used to predict the time delay to the onset of the major F2 transition associated with /I1/. Previous work suggests F2 onset frequency is sensitive to degree of gestural overlap in vocalic nuclei preceded by alveolar consonants. Preliminary results suggest (1) longer vocalic nuclei tend to be associated with F2 onset frequencies closer to the preceding consonantal articulatory locus, and (2) the linear relationship between F2 onset and time to target deteriorates above certain speaking durations, suggesting that the basic form of the gesture is altered at slower rates. [Work supported by DC 00319.]