Ham or hamster? Eye-tracking evidence of a clear speech benefit for word segmentation in quiet and in noise

This study examined whether intelligibility-enhancing hyperarticulated clear speaking styles improve word segmentation during real-time speech processing in quiet and in noise. English-speaking listeners heard clearly and conversationally spoken sentences in which the target (e.g. ham) was temporarily ambiguous with a competitor (e.g. hamster) across a word boundary (e.g. ham starting) while their eye fixations to target and competitor images were recorded. Relative to conversational speech, clear speech led listeners to fixate the target image over the competitor image to a greater degree, indicating facilitation of word segmentation. Such facilitation emerged in quiet and in noise even before disambiguating segmental information (e.g. /ɑ/ in starting) was available. A parallel clear speech benefit was not found when the disyllabic word (e.g. hamster) was the target. The findings suggest that improved word segmentation partly underlies the well-documented clear speech perceptual and cognitive benefits and may arise from the enhancements of multiple word boundary cues.