A qualitative dynamic analysis of reiterant speech production: Phase portraits, kinematics, and dynamic modeling

Abstract

The departure point of the present paper is our effort to characterize and understand the spatiotemporal structure of articulatory patterns in speech. To do so, we 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. Further quantitative analysis of articulator movement as a function of stress and speaking rate was indicative of a language-modulated dynamical system with linear stiffness and equilibrium (or rest) position as key control parameters. Preliminary modeling was consonant with this dynamical perspective which, importantly, does not require that time per se be a controlled variable.

Tongue movement kinematics in long and short Japanese consonants

“…Earlier work has shown a strong correlation between movement displacement and peak velocity in both speech and nonspeech movements (e.g., Cooke, 1980;Ostry et al, 1983;Kelso et al, 1985;Vatikiotis-Bateson and Kelso, 1993;Hertrich and Ackermann, 1997;Löfqvist and Gracco, 1997). The present study measured the average speed of the tongue movement during the acoustically defined closure/constriction for the consonant.…”

Tiers in articulatory phonology, with some implications for casual speech

“…The durational and segmental variations associated with differences in stress level can be simply accounted for in terms of dynamically defined articulatory movements (BrownIan & Goldstein, 1985;Kelso, Vatikiotis-Bateson, Saltzman, & Kay, 1985;. Decreasing the stiffness k of the "spring" for the stressed vowel results in a slower trajectory, which conesponds to the longer duration associated with stress.…”

Lip kinematics in long and short stop and fricative consonants

“…This follows from the strong correlation between movement displacement and peak velocity that has been observed in both speech and non-speech movements (e.g., Cooke, 1980;Ostry et al 1983;Kelso et al, 1985;Vatikiotis-Bateson and Kelso, 1993;Hertrich and Ackermann, 1997;Löfqvist and Gracco, 1997). One exception to this pattern can occur when a movement of one articulator is truncated by a following gesture, so that its movement displacement is decreased (e.g., Munhall et al, 1992;Harrington et al, 1995;Byrd et al, 2000).…”