Functional significance of the acoustic change complex, mismatch negativity, and P3a for vowel processing in native-English listeners and late learners of English

Abstract

The acoustic change complex (ACC), mismatch negativity (MMN), and P3a all provide indices of the neural processing of the types of acoustic changes that underlie speech and language perception. The goal of this study was to compare neural correlates of vowel processing for contrasts that have been shown to be easy to perceive in native-English speakers but more difficult for native-Spanish speakers. Processing of a vowel change from /I/ to /E/ was compared in a group of late learners of English and a group of monolingual English listeners (n = 15 per group). Preliminary analyses suggest differences in processing of the vowel change from /I/ to /E/ across the groups. Monolinguals processed the vowel change more rapidly and more accurately than bilinguals. The obligatory response to vowel onset showed a larger N1 for the bilinguals compared to the monolinguals. In addition, group differences were obtained in mean global field power (MMN and P3a were longer for bilinguals) and topography (current source density showed group differences for ACC P2 component, MMN, and P3a). Therefore, ACC, MMN and P3a all showed the effects of native language experience; however, these effects were not identical for each component.