Audio-visual speech perception in noise by first and second language listeners

![CDATA[Second language (L2) listeners' auditory speech perception is more vulnerable to noise than that of first language (L1) listeners. Impoverished auditory perception may cause L2 listeners to rely more on visual speech cues when perceiving speech in noise. The present study examined whether L1 and L2 perceivers might differ in their use of visual speech cues. In the experiment English-Spanish and Spanish-English bilingual participants were tested in a phoneme identification task across 16 English and 16 Spanish consonants (in the context of VCV syllables) that were presented in auditory-only, visual-only and auditory-visual conditions, with or without background 'babble' noise. The results showed that overall, L1 perceivers outperformed L2 perceivers across all conditions, and both groups improved in auditory-visual compared to auditory-only conditions. L2 listeners' performance showed a greater drop from in-clear to in-noise conditions compared to L1 listeners. Despite the discrepancy between L1 and L2 listeners in performance, the relative degree of improvement in auditory-visual compared to auditory-only conditions was the same for both L1 and L2 listeners. Further, auditory-visual integration efficiency measures showed no significant difference between the L1 and L2 listener groups. These results suggest that L1 and L2 users give similar weight to visual cues in speech perception and indicate that L2 listeners' vulnerability in perceiving acoustic speech cues in noise is not compensated for by better use of visual speech cues.]]