Auditory specialization for speech perception. (360G-Wellcome-084841_Z_08_Z)

We will examine the perceptual specialization for native-language phonemes by comparing adults with different native languages, using behavioural measures and MEG. The experiments will test languages and phoneme pairs that our previous work has suggested are affected by cross-language auditory processing differences: English /w/-/v/ for native Sinhala and English speakers, and English /r/-/l/ for native Japanese and English speakers. The first part of the proposal will involve behavioural exp eriments that manipulate the acoustic form of speech. We will construct non-speech stimuli to determine whether cross-language differences can be found for stimuli that fall short of being intelligible speech, and will use transformations of the speech signal (e.g., sinewave speech) to determine whether we can find cross-language differences when the acoustic form of intelligible speech is unnatural. The goal is to determine how acoustically close the stimuli need to be to natural speech in orde r for cross-language patterns of phonetic perception to emerge. The second part of the proposal will investigate these behavioural findings using the mismatch response (MMN) of MEG recordings. Our goal is to determine where and when these cross-language differences in phonetic processing occur.