Abstract:
Recent work has demonstrated that temporal lengthening of articulatory gestures adjacent to an intonational phrase boundary likely results from a lower underlying gestural stiffness. Magnetometer data from one subject (two more to be added) was examined to determine whether multiple levels of prosodic boundaries are distinguished in the spatiotemporal patterning of articulation. Eighty tokens were recorded of a /CVCV#CVCV/ sequence with five differing boundary conditions: (a) none, (b) a simple word boundary, (c) a boundary between elements in a list, (d) a vocative name boundary, and (e) an utterance boundary. The magnitude and duration of each consonantal closing and opening gesture, and the temporal latency between consonants were determined. Three statistically differentiated levels of interconsonant latency were found in the /CV#CV/ portion of the utterance---e,d>c>a,b---that results from differences in post-boundary closing durations. Lengthening of preboundary opening movements also occurs for the three largest boundaries---e,d,c>a,b. All gestural duration increases are accompanied by longer mean times to peak velocity indicating lower gestural stiffnesses. Additionally, the boundary-adjacent opening gestures are spatially larger before the three largest boundaries---e,d,c>a,b. Both spatial and temporal boundary effects on articulation will be described in a dynamical model. [Work supported by NIH.]