A functional imaging study of translation and language switching

TLDR

Switching refers to alternating between L1 and L2, and the study’s results are interpreted within the framework of cognitive control of language processes. The study investigates the neural systems underlying translation and language switching using PET imaging. PET scans were conducted on proficient German–English bilinguals while they translated or read words in L1, L2, or alternated between the two languages. Translation and language switching recruit distinct neural networks, with translation activating the anterior cingulate, subcortical and articulation regions, whereas switching engages Broca’s area and supramarginal gyri.

Abstract

The neural systems underlying translation and language switching were investigated using PET. Proficient German–English adult bilinguals were scanned whilst either translating or reading visually presented words in German (L1), English (L2) or alternating L1/L2. We refer to alternating L1/L2 as `switching'. The results revealed contrasting patterns of activation for translation and switching, suggesting at least partially independent mechanisms. Translation, but not switching, increased activity in the anterior cingulate and subcortical structures whilst decreasing activation in several other temporal and parietal language areas associated with the meaning of words. Translation also increased activation in regions associated with articulation (the anterior insula, cerebellum and supplementary motor area) arguably because the reading response to the stimulus must be inhibited whilst a response in a different language is activated. In contrast, switching the input language resulted in activation of Broca's area and the supramarginal gyri, areas associated with phonological recoding. The results are discussed in terms of the cognitive control of language processes.