Neuroimaging of the bilingual brain: evidence and research methodology

Abstract

Given that nowadays more than half of the world’s population is bilingual, the study of the neural basis of bilingual language processing has become a relevant and founding topic in the recent field of neuropsycholinguistics. This article has two main aims: 1) to discuss some methodological aspects related to the development of neuroimaging studies on language processing in the bilingual brain, and 2) to review neuroimaging data on language processing considering individual factors which have characterized the literature in bilingualism so far, for their impact on language architecture in the bilingual brain. Several studies have provided data on the role of age of acquisition, proficiency level, chronological age, learning method and language use on language organization in the bilingual brain. The variety of methodological approaches used and the lack of control of the various factors that can influence bilingual language processing have made it hard to draw conclusions on language circuitry in bilinguals. This discussion intends to contribute for the debate on the theoretical and methodological bases of the neurofunctional organization of languages in the bilingual brain.