Demonstrating effects of parameter dynamics on gestural timing
Elliot L. Saltzman, Dani Byrd · The Journal of the Acoustical Society of America · 2000
Speech movements have been modeled as goal-directed gestures whose activation-gated dynamics are those of critically damped point attractors. Recent work by ourselves and others has suggested that gestural parameter values are not fixed but rather vary as a function of a gesture’s position in the word and phrase. For example, lowering of gestural stiffness values has been hypothesized to underlie gestural lengthening adjacent to phrasal boundaries. Additionally, evidence exists suggesting that prosodic structure affects the relative timing between gestures. In earlier work, we have hypothesized that slowing at phrase boundaries can be implemented using nonconstriction gestures called pi-gestures (prosodic gestures) that act on the parameter values of all concurrently active constriction gestures in proportion to the activation level of the pi-gesture. In order to understand the potentially complex consequences of these parameter dynamics, we present a series of simulations involving different temporal arrangements of two constriction gestures coordinated with one another and with a prosodic gesture. The within- and between-gesture temporal patterning of the constriction gestures will be evaluated under the influence of pi-gestures of greater and lesser strength (activation) and duration. Simulation results will inform interpretation of natural kinematic articulatory data collected in movement tracking experiments. [Work supported by NIH.]