A QUALITATIVE DYNAMIC ANALYSIS OF REITERANT SPEECH PRODUCTION - PHASE PORTRAITS, KINEMATICS, AND DYNAMIC MODELING

An attempt is made to characterize and understand the spatiotemporal structure of articulatory patterns in speech. To do so, the authors removed segmental variation as much as possible while retaining the spoken act's stress and prosodic structure. Subjects produced two sentences from the 'rainbow passage' using reiterant speech in which normal syllables were replaced by /ba/ or /ma/. This task was performed at two self-selected rates, conversational and fast. Infrared LEDs were placed on the jaw and lips and monitored using a modified SELSPOT optical tracking system. As expected, when pauses marking major syntactic boundaries were removed, a high degree of rhythmicity within rate was observed, characterized by well-defined periodicities and small coefficients of variation. When articulatory gestures were examined geometrically on the phase plane, the trajectories revealed a scaling relation between a gesture's peak velocity and displacement.