Neural bases of bilingual language production

Languages have grammatical rules that define how words are used in different contexts, such as adding "-s" to a word to make it plural. People who speak more than one language must use different sets of rules depending on which language they are speaking. Multilingualism raises important questions about how the brain processes more than one language effectively. This project aims to study how this is accomplished by measuring brain responses while bilinguals produce words in different languages with different grammatical rules. Through these results, the project aims to provide insights into the neurobiology of language more generally and answer questions about how people learn multiple languages. The project also creates a large, publicly available bilingual brain database, provides opportunities for the public to learn more about how the brain processes language, and provides training for students in advanced neuroscience techniques. In detail, the project examines bilingual speech production through a series of experiments that measure brain responses using magnetoencephalography (MEG) while people say words that require them to produce a morphological change. By examining similarities in how morphological rules are used across multiple languages, the project aims to characterize when and where in the brain these processes take place. This approach can distinguish different theoretical models of bilingual language processing, specifically models that posit shared neural mechanisms across languages versus models that suggest distinct representations for each language. The project also examines how these processes are affected by the age of acquisition of a second language, potentially addressing important questions about second language learning. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.