Abstract:

This investigation examined the sequencing of lip and jaw movement onsets and peak velocities for bilabial closure as a function of speaking rate, phonetic context, and position of the closing gesture within the utterance. Articulatory movements were transduced using head-mounted strain gauge transducers. Five normal speakers repeated the target words /paep/, /paeps/, and /paepst/, within the carrier phrase, ``Now say ____ again.'' Speaking rate (normal, fast, and slow) was manipulated using a magnitude production scale with no external time constraints. Most subjects demonstrated consistency in the sequencing of articulatory events at fast speaking rates, while normal and slow rates evidenced increasing variability. The position of the closing gesture within the utterance also affected the sequencing, with the closing gesture for the first /p/ usually exhibiting greater consistency than the closing gesture for the second /p/. The production of a single consonant versus consonant clusters appeared to have little impact on the sequencing of articulatory events for bilabial closure. Despite these general trends, individual subject differences were evident, with some speakers demonstrating greater consistency than others. These findings suggest that temporal ordering of articulatory events is flexibly organized based on the specific task demands. [Work supported in part by NSERC.]