ASA 125th Meeting Ottawa 1993 May

2aSP10. Effects of speaking rate and stress on vowel durations and formant structures.

Janet W. Stack

Dept. of Psychol., Univ. of South Florida, Tampa, FL 33620

The effects of speaking rate and stress on the temporal and spectral quality of vowels in four adult male speakers were evaluated. Conversational style speech was used from which four vowels in two target words were analyzed. Target words were produced in two different sentence stress conditions. Vowel durations were measured, and formant values were obtained at the one-fourth, one-half, and three-fourths points of the syllables. Rapid rate tokens were consistently shorter in duration than normal rate. There was no differential duration shortening between stressed and unstressed words or vowels. Speakers were very consistent in their overall sentence compression, but word and vowel compressions showed nonsystematic individual differences. Target undershoot (any deviation greater than 1 Bark from the stressed normal rate condition) was found in only one speaker, for the first formant of one vowel. Formant movement from the one-fourth to the three-fourths point was not affected by rate or stress (determined as any change of more than 0.1 log unit from the stressed normal rate condition) in any speaker. [Work supported by NIDCD.]