I Scream for Ice Cream: Resolving Lexical Ambiguity with Sub-phonemic Information

This study uses a response mouse-tracking paradigm to examine the role of sub-phonemic information in online lexical ambiguity resolution of continuous speech. We examine listeners' sensitivity to the sub-phonemic information that is specific to the ambiguous internal open juncture /s/-stop sequences in American English (e.g., "place kin" vs. "play skin"), that is, voice onset time (VOT) indicating different degrees of aspiration (e.g., long VOT for "in" vs. short VOT for "sin") in connected speech contexts. A cross-splicing method was used to create two-word sequences (e.g., "place kin" or "play skin") with matching VOTs (long for "in"; short for "sin") or mismatching VOTs (short for "in"; long for "sin"). Participants (n = 20) heard the two-word sequences, while looking at computer displays with the second word in the left/right corner ("KIN" and "SKIN"). Then, listeners' click responses and mouse movement trajectories were recorded. Click responses show significant effects of VOT manipulation, while mouse trajectories do not. Our results show that stop-release information, whether temporal or spectral, can (mis)guide listeners' interpretation of the possible location of a word boundary between /s/ and a following stop, even when other aspects in the acoustic signal (e.g., duration of /s/) point to the alternative segmentation. Taken together, our results suggest that segmentation and lexical access are highly attuned to bottom-up phonetic information; our results have implications for a model of spoken language recognition with position-specific representations available at the prelexical level and also allude to the possibility that detailed phonetic information may be stored in the listeners' lexicons.