A new study by researchers from Harvard University, the Massachusetts Institute of Technology (MIT) and Carleton University has found the brain’s language network responds differently to a native language, than additional languages.
The study published in academic journal Cerebral Cortex, further explored existing findings on the language center in the brains of people who speak five or more languages, otherwise known as polyglots.
Researchers primarily examined what happens in the brains of polyglots when they listen to familiar languages in which they have varying levels of knowledge and proficiency.
Using functional magnetic resonance imaging (fMRI) and a group of 34 polyglot participants, the team studied the patterns and activity in the brain’s language center. Results showed that the same areas of the language center ‘lit up’ when participants were listening to languages learned later in life, but activity significantly lessened when listening to their native tongue.
Among the participants, sixteen of the participants spoke 10 or more languages, including one who spoke 54 languages with at least some proficiency.
Each participant was scanned (fMRI) as they listened to passages read in eight different languages. These included their native language, a language they were highly proficient in, a language they were moderately proficient in, and a language in which they self-identified as having low proficiency.
They were also monitored while listening to four languages they have no proficiency in. Two of these were languages from the same linguistic family (e.g. Romance languages) as a language they could speak, and two were languages completely unrelated to any they spoke.
The team’s findings suggested an almost-innate-like processing method for one’s native language, requiring minimal effort.
Evelina Fedorenko, an associate professor of neuroscience at MIT, a member of MIT’s McGovern Institute for Brain Research, and the senior author of the study explained “Something makes it a little bit easier to process — maybe it’s that you’ve spent more time using that language — and you get a dip in activity for the native language compared to other languages that you speak proficiently,”
In 2021, Fedorenko’s team first discovered that the language network in the brains of polyglots was less active when listening to their native language than the language networks of people who speak only one language. The 2024 study expands on these findings, whereby the lab wanted to focus on what happens to the brain in response to languages with varying levels of proficiency.
Fedorenko added “With polyglots, you can do all of the comparisons within one person. You have languages that vary along a continuum, and you can try to see how the brain modulates responses as a function of proficiency,” –
“As you increase proficiency, you can engage linguistic computations to a greater extent, so you get these progressively stronger responses. But then if you compare a really high-proficiency language and a native language, it may be that the native language is just a little bit easier, possibly because you’ve had more experience with it,”
Researcher Malik-Moraleda says “What we’re seeing here is that the language regions are engaged when we process all these languages, and then there’s this other network that comes in for non-native languages to help you out because it’s a harder task.”
In this study, the majority of participants began studying their non-native languages as teenagers or adults. In future work, the researchers hope to study people who learned multiple languages from a very young age.
They also plan to study people who learned one language from infancy but moved to an English-speaking country at a very young age, taking on English as their dominant language. This research will explore the effects of proficiency versus age of acquisition on brain responses.