The articulatory kinematics of accent

Abstract

Two recent kinematic studies of syllables with bilabial consonants suggest different dynamic accounts of the durational increase associated with stress: Kelso et al. [J. Acoust. Soc. Am. 77, 266–280 (1985)] interpret regression curves for peak velocity against displacement as evidence that lower-lip gestures in stressed syllables are less stiff, whereas Nittrouer et al. [J. Acoust. Soc. Am. 85, 1653–1661 (1988)] show that the upper-lip closing gesture begins at a later phase relative to the jaw opening gesture. Preliminary results from a kinematic study of accented syllables suggest a resolution of the discrepancy. Jaw opening and closing gestures for pop and poppa embedded in sentences that varied the placement of the nuclear pitch accent (sentence stress) were looked at. When accented, gestures were substantially longer, but the velocity-displacement regression curve showed no decrease in slope, contra Kelso et al. Also, a comparison of observed syllable durations to those predicted by the velocity-displacement ratios showed that this stiffness index alone cannot account for the greater length. Rather, an accented syllable is longer probably because the closing gesture is later, in accordance with Nittrouer et al. The seemingly contradictory pattern in Kelso et al. may be an artifact of including reduced syllables with unaccented full syllables in a single “unstressed” category. [Work supported by the NSF.]