Kenneth J. de Jong, Byung-jin Lim, and Kyoko Nagao
Dept. of Linguist., Indiana Univ., 322 Memorial Hall, Bloomington, IN 47405
Tuller and Kelso (JSHR, 1991) show the relative timing of peak glottal opening and oral closure in repetitive /ip/ production differs between /ip/ and /pi/ productions. Also, as repetition rate increases, the timing in /ip/ merges with that in /pi/. The authors interpret this to indicate two stable regions in glottal-to-oral phasing, one for codas and one for onsets. The current paper examines a similar corpus of glottal transillumination traces of repeated syllables, which includes both labial and lingual stops. Preliminary examination of peak glottal timing with respect to acoustic landmarks indicating closure shows the same pattern of timing differences at slow rates and neutralization at fast rates. However, peaks in the transillumination traces often do not indicate glottal abduction for the consonant, but rather indicate a relatively open glottis for vocalic voicing, happening in the context of glottal stoppage at the onset of the vowel. In addition, coronal codas exhibit cycle-to-cycle variation from glottalized to abducted voiceless forms. Thus while rate does induce stepwise changes in glottal activity, phasing, in the sense of relative timing, does not account for many of the rate effects. Rather, rate appears to be inducing a recomposition of the gestures which comprise the speech.