Duration and context speech rate as cues to lexical perception and word segmentation.

Abstract

Duration and speech rate are traditionally assumed to be filtered out before lexical lookup takes place, although these factors are known to influence phoneme perception. Here, the hypothesis was investigated that duration can affect both perceived lexical identity, as well as the perceived number and implied locations of word boundaries relative to the speech signal. Experiment 1 was a production study which investigated durations of vocalic portions of phonetically similar versions of target word strings which differed in their number of syllables (e.g., cease versus see us); these target word strings were spoken in semantically neutral context sentences. As expected, vocalic durations in target strings with fewer syllables were shorter than those with more syllables. In Experiment 2, the relative durations of vocalic portions of target strings in sentences from Experiment 1, as well as sentential context speech rate, were manipulated using speech resynthesis. Relative duration and context speech rate both affected the words that participants heard, as well as the implied number of phonemes and imputed locations of word boundaries. These findings indicate that duration plays a significant and underinvestigated role in spoken word recognition and word segmentation.