Bilinguals in the making: Language exposure and neural specialization in the first years of life

Objective

Most infants in the world grow up acquiring two languages, and they succeed in this task despite receiving language exposure that is quantitatively and qualitatively different from monolinguals. Based on previous monolingual-centered research, bilingual exposure patterns are expected to lead to delays in the acquisition of language-specific competence, but this effect is not observed across bilingual populations. Thus, existing language acquisition frameworks do not allow for accurate prediction of individual language outcomes for infants growing up in complex multilingual environments. Bilingual-LENS is the first large-scale longitudinal and multidisciplinary investigation to determine the quantity, quality, and timing of early bilingual exposure that accurately predict bilingual infants’ individual language outcomes. I will combine neuroimaging, neurophysiological, and observational methods in three longitudinal studies to assess bilingual infants’ language development from birth until 24 months of age. I will focus on three core components: (1) neural maturation, (2) stimulation through language exposure, and importantly, (3) the maturation-exposure interaction. Specifically, I will investigate the development of the maturation-exposure interaction over time, and its role in the continuous fine-tuning of infants’ perceptual sensitivities to their native languages and their developing dual-language competence. I predict that individual differences in the quantity and quality of infants’ speech input will determine their neural specialization for language processing with consequences for linguistic attainment later in childhood. As a result, Bilingual-LENS will capture bilingual language development as it unfolds over time, and it will produce a novel framework of language acquisition that systematically weighs the maturational and environmental factors predicting individual children’s dual-language proficiency.