Bilingual language processing relies on shared semantic representations that are modulated by each language

Abstract

AbstractBillions of people throughout the world are bilingual and can understand semantic concepts in multiple languages. However, there is little agreement about how the brains of bilinguals represent semantic information from different languages. Some theories suggest that bilingual speakers’ brains contain separate representations for semantic information from different languages, while others suggest that different languages evoke the same semantic representations in the brain. To determine how the brains of bilinguals represent semantic information from different languages, we used functional magnetic resonance imaging (fMRI) to record brain responses while participants who are fluent in both English and Chinese read several hours of natural narratives in each language. We then used this data to specifically and comprehensively compare semantic representations between the two languages. We show that while semantic representations are largely shared between languages, these representations undergo fine-grained shifts between languages. These shifts systematically alter how different concept categories are represented in each language. Our results suggest that for bilinguals, semantic brain representations are shared across languages but modulated by each language. These results reconcile competing theories of bilingual language processing.