Jaw displacement and F0 in contrastive emphasis.

Abstract

This study examines the relationship between highest F0 (within the sonorant portion of the syllable) and maximum jaw displacement (lowest vertical position of the mandible in reference to the maxillary occlusal plane) in utterances with contrastive emphasis. Acoustic and articulatory recordings were made using the x-ray microbeam facilities at the University of Wisconsin [J. Westbury and O. Fujimura, J. Acoust. Soc. Am. Suppl. 1 85, S98 (1989)]. Three American English subjects produced question–answer sentences like ‘‘Is it 599 Pine Street? No, it’s 59FIVE Pine Street,’’ reading from a monitor display with a marking on the digit to be emphasized either in initial, middle, final position, or with no emphasis. The data showed positive correlation between jaw opening and F0 for syllables spoken with contrastive emphasis, but no correlation for nonemphasized syllables. One would expect two opposite biomechanical effects of jaw opening on F0: a positive effect by the action of jaw opening muscle on larynx elevation, and a negative effect by passive hyoid retraction due to jaw lowering. These findings suggest that prosodic contrast may be achieved by reorganization of interactive control of jaw opening and F0. Possible acoustical, physiological, and phonological ramifications of these findings are discussed. [Work supported by NSF SBR-951199B and ATR/ITL, Kyoto, Japan.]