Prof. Loraine Obler (CUNY)
Plasticity has been called upon to account for the critical period in second-language (L2) acquisition and for related sensitive periods for different linguistic aspects of it. At the same time it can be employed to account for individual differences in L2 learning and acquisition at older ages. It has also been considered to underlie the apparent cognitive advantages of bilingualism for children and older adults who presumably practice cognitive control more often than monolinguals, and even for bilinguals and multilinguals’ later diagnoses of dementia. Such plasticity may be considered ‘additive’; that is, by practicing a set of skills, bilinguals’ and multilinguals’ inter-neuronal connectivity is enhanced.
Plasticity, however, also entails a second set of phenomena that require pruning of connections and defacilitation of neuronal connections. Such physiological phenomena, I will argue, underlie language attrition (the over-riding of one language by another that has become more dominant) and syntactic and lexical influence of a later language on an earlier one. Concurrent additive and subtractive plasticity effects can explain mutual-interference effects of Voice Onset Time adjustment in early bilinguals.