Kuipers, J. R. & Thierry, G.
ESRC Centre for Research on Bilingualism, Bangor University, Bangor, UK
Children raised in a bilingual environment are faced with the daunting task of learning to extract meaning from speech input that can differ between caregivers and, depending of the social context, also within caregivers. From birth onwards, however, infants seem to be able to distinguish between the languages spoken, and in their first year of life, learn to distinguish between native and non-native phonetic contrasts. Here we tested monolingual and bilingual toddlers’ and adults’ event-related potential (ERP) responses to an unexpected change in language. Both adult and children participant groups were presented with the same pairs of pictures and spoken words. The language spoken was occasionally changed from English to Welsh in a variant of the oddball paradigm while ERP responses were recorded. The results showed that the adult bilinguals differentiated between the languages spoken in mean P2 amplitudes, reflecting fast language change detection, and mean P600 amplitudes, reflecting language monitoring strategies. The adult monolinguals only showed an N400 modulation by the Welsh words reflecting the difficulty of semantically integrating unknown words. The results of the toddler groups showed more positive ERP responses to Welsh words in both groups. However, the bilinguals’ response was significant only between 80 - 280 ms after word onset whereas the monolinguals’ response was significant from 350 - 550 ms after word onset. These results suggest that a bilingual’s sensitivity to phonemic language cues form at an early age but that their language awareness may develop later in life. By comparison, monolinguals did not distinguish between the languages spoken until the time window associated with semantic integration. Hence, monolinguals seem less sentitive to a language change than bilinguals.