Articulatory and acoustic relations during variations in speech rate and loudness

Abstract

Rate and loudness manipulations are standard treatment strategies used to recover speech intelligibility. Although numerous studies have characterized the articulatory changes that result from these manipulations, their influence on segmental aspects of the acoustic signal are not well understood. This preliminary investigation examines acoustic, electromyographic (EMG), and kinematic changes associated with elicited modulations of rate and loudness in typically speaking individuals. Participants were instructed to repeat a sentence five times while incrementally increasing or decreasing either their speaking rate or loudness with each repetition. Acoustic measures included total utterance durations, segment durations, vowel formant frequencies, and trajectories. Displacements of the upper lip, lower lip, and jaw were captured in three dimensions using a computerized video movement-tracking system. Surface EMG signals were recorded from the right masseter, right temporalis, and submental group. Data analyses were directed toward describing the degree of correspondence among parametric changes in muscle activity, articulatory kinematics, and segmental features of the acoustic signal that result from nearly continuous changes of rate and loudness. [Work supported by NIH-NIDCD.]