Bilingualism: A challenge for the developing brain

Abstract

Neurophysiological studies have demonstrated that first language (L1) and second language (L2) processing are not necessarily represented in different neural regions. However, factors such as language competence and age at onset of L2 acquisition can influence the representation of L2 in the "bilingual braino". Bilinguals who acquired a second language later in life were frequently reported as having different activation patterns for linguistic tasks as compared to bilinguals with an early age at onset of L2 acquisition. Furthermore, later acquisition of L2 has often been associated with a poorer language outcome. Previous neuroscientific research on bilinguals primarily addressed the language outcome of bilinguals in adolescence and adulthood, but there remains a significant gap in knowledge regarding the developmental trajectory of language capacities that has only recently started to be systematically addressed. The current longitudinal study presents an examination of 3 bilingual children with the same duration of bilingual language exposure but different ages at onset of L2 acquisition. Our observations indicate a relationship between the age at onset of acquisition and the grammatical competence of L2 later in life. However, lexicon and reading competence were not influenced by age at onset of L2 acquisition. Furthermore, the L2 system of the child who was the oldest at the onset of L2 acquisition displayed the most robustness after a temporary change in linguistic environment. To generalize these findings and detect general developmental trends in children acquiring 2 or more languages at a time, more interdisciplinary research on the developing "multilingual braino" is needed. © Georg Thieme Verlag KG Stuttgart · New York.