Abstract
Bilingual language production requires both language knowledge and language control in order to communicate in a target language. Learning or improving a language in adulthood is an increasingly common undertaking, and this has complex effects on the cognitive and neural processes underlying language production. The current fMRI experiment investigated the functional plasticity of verbal production in adult language learners, and examined the dynamics of word retrieval in order to dissociate the contributions of language knowledge and executive control. 34 adults who were either intermediate or advanced L2 learners, underwent MRI scanning while performing verbal fluency tasks in their native and new languages. A multi-pronged analytical approach revealed (i) time-varying contributions of language knowledge and executive control to verbal fluency performance, (ii) significant learning-related changes in the functional correlates of verbal fluency in both the native and new languages, (iii) no effect of learning on lateralisation, and (iv) greater functional coupling between language and language control regions with greater L2 experience. Collectively, our results point to significant functional plasticity in adult language learners that impacts the neural correlates of production in both the native and new languages, and provide new insight into the widely-used verbal fluency task.
