Influences of preceding speech rate and prosodic position on listeners’ perception of durational cues

Abstract

Research suggests that listeners incorporate expectations about the temporal organization of prosodic structure in their perception of durational cues. Steffman (2019, JASA) tested sensitivity to phrase-final lengthening: listeners categorized a “coat”∼“code” vowel duration continuum (increased duration cues voicing) in a carrier phrase. The target was either phrase-medial or phrase-final. Listeners required longer vowel durations for a “code” response when the target was phrase-final, suggesting an expectation of lengthening in final position influenced perception of duration. The present study tests how listeners are sensitive to preceding speech rate changes in tandem with prosodic/positional effects. Using the same stimuli as Steffman (2019), preceding speech rate was manipulated orthogonally to position (2 × 2): a target was phrase-final or medial, preceded by either slow or fast precursor speech. Results show independent influences of rate and position on categorization, which are differently localized. Positional effects are concentrated at longer vowel durations which align with typical durations for phrase-final vowels. Rate effects localize in the middle region of the continuum. These results offer some support for the idea the prosodic effects in perception depend on durational patterns in the language, and extend Steffman (2019) to show that listeners integrate both speech rate and prosodic information in perception.