Multi-timescale Dynamical Interactions Between Speech Rhythm and Gesture
Sam Tilsen · UC Berkeley Phonology Lab Annual Reports · 2008
Temporal patterns in speech occur on multiple timescales.Regularities in such patterns have been observed between gestures, which are relatively quick, and between rhythmic units, which are slower.Previous work has shown that patterns in both domains can be modeled with oscillatory dynamical systems.This paper builds upon prior work by investigating how gestural and rhythmic patterns interact.An experiment was conducted in which speakers repeated the phrase "take on a spa" to a metronome with several different rhythms, some of which were more difficult to produce than others.Gestural kinematics were recorded using electromagnetic articulometry, allowing for both rhythmic and gestural variability to be measured.Relative timing of jaw, lip, and tongue movements associated with the [sp] cluster in the word "spa" were analyzed.Significant relations were found between rhythmic variance and gestural variance.In addition, within-gesture effector synergies differed systematically across rhythmic conditions.These results demonstrate an interaction between rhythmic and gestural systems.A dynamical model of phase-coupled oscillators is presented, which can simulate the observed variability patterns.