Perceiving foreign-accented auditory-visual speech in noise : the influence of visual form and timing information

The present study examined the extent to which visual form and timing information assisted in the perception of native English and Japanese-accented English speech in noise. We also examined whether the degree of visual facilitation would be mediated by the talkers' English experience. Thirty native Australian English listeners performed a speech perception in noise task with English sentences produced by inexperienced and experienced Japanese talkers as well as a native English talker. The Japanese speakers were selected from a previous study where acoustic analyses showed that the speech rhythm of the inexperienced talker was more influenced by their native language than to the experienced one. The stimulus sentences were presented under the three conditions: Audio-only, Audio-visual (visual form and timing) and Audio-visual with mouth covered (visual timing only). The results showed a visual timing facilitation effect for the stimuli produced by the experienced but not in the inexperienced Japanese talker. A facilitative form effect was found for all the talker groups but the size of this effect decreased as the degree of the non-native experience decreased. Our findings illustrate the influence of L2 talker's experience on the effectiveness of their visual form and timing cues