What Can Aphasia Tell Us about How the First-Acquired Language Is Instantiated in the Brain?

Recent neurolinguistic theories converge on the hypothesis that the languages of multilingual people are processed as one system in the brain. One system for the multiple languages is also at the core of a translanguaging framework of multilingualism-a framework that focuses on each speaker's complete linguistic repertoire rather than on the separate languages they know. However, evidence from neuroimaging studies suggests at least some nonoverlapping activations of the first-acquired language (L1) and other (non-L1) languages of multilingual people, especially when the age of acquisition and/or levels of proficiency differ across the languages. Neurolinguistic studies of acquired language disorders have demonstrated that in multilingual people who experience language impairments due to brain lesion, L1 may be less impaired or better recovered than non-L1. This paper explores the evidence available to date from the study of acquired language impairment regarding this potential primacy of the first-acquired language. Findings suggest that L1 may be better preserved in many instances of language impairment, challenging the theory of a single system for multiple languages.