ASA 127th Meeting M.I.T. 1994 June 6-10

1pSP43. Phase resetting in speech. I. Repetitive utterances.

Haskins Labs., 270 Crown St., New Haven, CT 06511-6605

Bruce Kay

Brown Univ., Providence, RI

This experiment addresses the sequential dynamics governing bilabial and laryngeal movements in speech. Two subjects produced the repetitive sequence /p(ae ligature)p(ae ligature).../ while a randomly timed, transient mechanical load was applied to the lower lip in 80% of 300 productions; the load pulled the lip downwards. Movements of the lips, the jaw, and the larynx were recorded using optoelectronic techniques. For each trial, successive peak labial openings and laryngeal abductions were used to define a series of lip aperture (upper lip minus lower lip) and laryngeal cycles, respectively. Phase resetting analyses were performed separately on the labial and laryngeal cycles in order to examine the steady-state phase shifts induced as a function of the cycle phase of perturbation delivery. Preliminary analyses indicate that steady-state shifts occurred for both lips and larynx, but no steady-state shifts occurred in the relative phasing of these articulators. Analyses of the cycles that were actually perturbed showed that the steady state effects were primarily due to durational changes induced in these perturbed cycles. Results will be discussed in relation to the dynamics of intergestural timing, and will be used to interpret the results of a companion perturbation study on discrete speech sequences. [Work supported by NIH.]