Articulatory dynamics of fluent utterances of stutterers and nonstutterers.

High speed cineradiography is used to describe the kinematics and spatial and temporal organization of perceptually fluent speech gestures for six stutterers and seven normal speakers. Movements of the lower lip and jaw are analyzed in the CVCs/mam/,/pap/, and /bab/. The results indicate that stutterers consistently show longer durations between movement onsets, achievements of peak velocity and voice onsets than normal speakers. Stutterers also show longer steady state positioning for the lip and jaw during vowel production and a greater asynchrony between lip and jaw movement. The results suggest that in perceptually fluent utterances the organization of events necessary for speech production differs between groups of stutterers and normal speakers.