A bilingual advantage in infant pitch processing

Behavioural studies report differences in monolingual and bilingual infants' non-native lexical tone perception. The current study explored the degree to which infants' linguistic experiences alter their pitch processing along the developmental trajectory using electroencephalogram (EEG). Forty 5-6- and 11-12- month monolingual and bilingual Australian infants with no prior tone language exposure underwent a passive oddball EEG task involving a contracted Mandarin tone contrast. At 5-6 months, all infants exhibited positive mismatch responses (MMR) to the contrast. At 11-12 months, however, MMRs were observed for bilingual infants only. Results indicate early neural discrimination of lexical tones even when the feature is absent from infants' native phonemic inventory, although such sensitivity was immature. Furthermore, while 11-12-month-old monolingual infants lose sensitivity at perceptual narrowing offset, bilingual infants' displayed immature neural responses. Implications of differences in the neural signature between infants from different language backgrounds are discussed.