Prosodic phrasing mediates listeners’ perception of temporal cues: Evidence from the Korean Accentual Phrase

In two experiments we examine how listeners make reference to prosodic phrasing in their perception of temporally cued segmental contrasts. We test how the prosodic-structurally conditioned modulation of segmental cues (in domain-initial strengthening) translates into speech perception. We adopt the test case of stop contrasts in Seoul Korean (aspirated versus fortis), which are cued by vowel duration and voice onset time (VOT). The phrasing manipulation was carried out at the level of the Accentual Phrase (AP), a small phrase that is marked by intonational features. The AP was chosen because it was possible to create two prosodic phrasing contexts (AP-initial versus AP-medial) by manipulating only f0 before the target segment with the duration of contextual segments unchanged, controlling for temporal context effects. In Experiment 1, listeners shift their perception of a VOT continuum based on phrasing, in line with the domain-initial strengthening pattern of post-stop vowel lengthening, where AP-initial post-fortis vowels are lengthened. Experiment 2 shows that vowel duration is used as a cue to the contrast and that perceptual categorization of vowel duration itself is also mediated by contextual phrasing information. Results thus suggest that prosodic phrasing, signaled by intonation only, mediates perception of the segmental contrast, with temporal context controlled. We discuss these findings in terms of their implications for the role of phrasing in segmental perception and in processing.