Language attrition: A matter of brain plasticity?

While it has long been assumed that brain plasticity declines significantly with growing maturity, recent studies in adult subjects show grey and white matter changes due to language learning that suggest high adaptability of brain structures even within short time-scales. It is not known yet whether other language development phenomena, such as attrition, may also be linked to structural changes in the brain. In behavioral and neurocognitive research on language attrition and crosslinguistic influence, findings suggest high plasticity as language interaction patterns of bilingual speakers change constantly and from early stages of language acquisition onwards. In this paper we will speculate on possible links between brain plasticity and L1 attrition in adult bilinguals, with particular attention to a number of factors that are put forward in memory frameworks in order to explain forgetting: time elapsed, frequency of L1 use, and interference from L2. In order to better understand the time-scales involved in the plastic changes during bilingual development, we then discuss some recent studies of re-exposure to L1 in formerly attrited immigrants, and their implications with respect to brain plasticity.