Concurrent Effects on Duration II: Prevocalic and Postvocalic Consonants

Author: Dawn M. Behne, Lynne C. Nygaard

Abstract:
The duration of a vowel can be affected by speaking rate, focal stress, sentence position, posvocalic voicing and inherent vowel duration. Having confirmed the individual effects of these factors on vowel duration, the goal of this study was twofold: (1) to describe their effects on the timing of consonants enighboring an affected vowel, and (2) to characterize the internal timing of the syllable when these factors are combined in the same sentence. Using the vowels /I, o, a, æ/, conversations were developed with /kVt/ and /kVd/ as target words. In each conversation C1VC2 targets occurred in initial or final sentence position, and were either focused or nonfocused by the discourse. Twelve subjects produced each conversation at three speaking rates. The results indicate that, like vowels, the closure durations of prevocalic and postvocalic consonants are affected by speaking rate, focal stress, and durations. These findings suggest that speaking rate and focal stress globally affect the internal timing of a syllable, whereas sentence position, postvocalic voicing, and inherent vowel duration have a more local effect on segment duration. And, when converging on a syllable, these factors individually influence the syllable's internal timing within flexible upper and lower limits.