Variability in bimodal spoken language processing by native and nonnative speakers of English: A closer look at effects of speech style

Experiments using the gating paradigm investigated the influence of speech style (unscripted vs. scripted), visual cues from a talker's face (auditory-visual vs. auditory-only presentations), word length (one vs. two syllables) and initial consonant (IC) visual category in spoken word identification by native- (NSs) and nonnative speakers (NNSs) of English. Two talkers were videotaped in separate conversations with the author on various topics (unscripted speech) with the camera focused on the talker's face. They later recorded selected sentences as scripted speech. In Experiment 1, target words were excised from sentences, gated, and presented to NSs and NNSs. Results for both groups showed significantly earlier identification with visual cues and for bisyllabic vs. monosyllabic words, and significant interaction of speech style and IC category across talkers. For Talker A, identification of unscripted monosyllabic words in some IC categories was earlier than the scripted versions. For this talker, words beginning with // were identified later than others; for Talker B, they were the earliest to be identified. For NNSs, the AV advantage was accentuated for words beginning with /, w, / in unscripted speech by Talker A, and for //- and /l/-initial words in both speech styles by Talker B. Experiment 2 presented the preceding sentence context with the gated word to NSs. Results revealed earlier identification in AV presentation and for unscripted vs. scripted words by Talker A. With context, word length was not significant. Findings highlight the priming role of visual cues, and the talker- and context-dependent nature of bimodal spoken language processing, but do not support a strict conversational-clear speech dichotomy.