K. Bretonnel Cohen
Mary E. Beckman
Linguist. Dept., Ohio State Univ., Columbus, OH 43210-1298
Ohio State Univ.
Intonation pattern and syllable duration are thought to be the most salient perceptual cues to phrase stress. However, intonation is an inherently ambiguous cue, since not all English pitch accents involve higher pitch on the accented syllable, and because there are stress contrasts at a lower level, where stress cannot be equated with accentuation. Duration, too, is ambiguous, since it can cue other prosodic contrasts, such as phrasal position. This study examines finer-grained timing cues to stress. A strain-gauge system was used to examine jaw opening and closing movements in /p(open aye)p/ sequences in intonationally accented full-voweled syllables, unaccented full-voweled syllables, and completely stressless (reduced-vowel) syllables produced by four speakers. Measured values for movement duration, displacement, and velocity were consistently larger in accented than in unaccented full-voweled syllables. However, these differences were nowhere near as large as the differences between full- and reduced-vowel syllables. Reduced syllables also had steeper velocity-displacement relationships, suggesting a durational difference at the level of gestural dynamics as well. However, no such consistent difference was observed between accented and unaccented full-voweled syllables. These results support the notion that stress contrasts are not uniformly interpreted in the phonetics at different levels.