Phrase final lengthening modulates categorization of vowel length as a cue to obstruent voicing in English

Abstract

This study explores how perceptual sensitivities to contextual variability might extend to prosodically conditioned variation, a recent topic of interest in the literature. In English, vowel duration is reliably longer preceding a voiced obstruent, as opposed to a voiceless obstruent, and listeners use preceding length as a cue to obstruent voicing. Segmental duration also co-varies systematically with prosodic position, being longer phrase-finally (in phrase-final lengthening). With this in mind, The present study tested the extent to which listeners’ categorization of word-final obstruents is influenced by the prosodic position of the target sound. Participants heard a continuum that varied only in vowel length, and categorized stimuli as either "coat" or "code." Prosodic position in a carrier phrase was manipulated by splicing the target word into either a phrase-final or phrase-medial context. Results suggest expectations about phrase-final lengthening shift categorization, with significantly longer vowel durations required in phrase-final position for a "code" response. These results are discussed in terms of their implications for further research and in relation to speech rate normalization.