A new study by researchers at Harvard University, the Massachusetts Institute of Technology (MIT) and Carleton University has found that the brain’s language network responds differently to a native language than to other languages.
The study, published in the journal Cerebral Cortex, examined existing knowledge about the language center in the brain of people who speak five or more languages - also known as polyglots.
The researchers primarily investigated what happens in the brains of polyglots when they hear familiar languages in which they have different levels of knowledge and skills.
Using functional magnetic resonance imaging (fMRI) and a group of 34 polyglot participants, the team examined the patterns and activity in the language center of the brain. The results showed that the same areas of the language center “lit up” when participants heard languages they learned later in life. However, the activity decreased significantly when they heard their native language.
Sixteen of the participants spoke ten or more languages, including one who had at least some fluency in 54 languages.
Each participant was scanned using fMRI while listening to passages of text in eight different languages, including their native language, a language they spoke very well, a language they spoke moderately well, and a language they reported having only a low level of proficiency.
They were also monitored while listening to four languages they did not speak. Two of these languages were from the same language family (e.g. Romance languages) as a language they could speak, and two were completely unrelated to the languages they spoke.
The team’s results suggested an almost innate method of processing the native language that requires minimal effort.
Evelina Fedorenko, an associate professor of neuroscience at MIT, a member of MIT’s McGovern Institute for Brain Research, and lead author of the study, explains: “Something makes it a little easier to process – maybe it’s because you’ve spent more time with the language – and that you spend less time with your native language than with other languages you’re fluent in.”
In 2021, Fedorenko’s team discovered for the first time that the language network in the brains of polyglots was less active when listening to their native language than the language network of people who speak only one language. The 2024 study builds on these findings, with the lab seeking to focus on what happens in the brain in response to languages at different proficiency levels.
Fedorenko added: “With polyglots, you can do all 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 language proficiency.” –
“As you become more proficient, you can do more linguistic computation, so you get these increasingly stronger responses. But then when you compare a really high-proficiency language and a native language, it may be that the native language is just a little bit easier, perhaps because you have more experience with it.”
Researcher Malik-Moraleda says: “What we see here is that the language regions are involved when we process all these languages. And then there is this other network that steps in and helps you with foreign languages because that is a more difficult task.”
In this study, the majority of participants began learning their foreign language in their teens or adulthood. In future work, researchers hope to study people who learned multiple languages at a very young age.
They also plan to study people who learned a language from an early age but moved to an English-speaking country at a very young age and adopted English as their primary language there. This research will examine the effects of language proficiency compared to age of acquisition on brain responses.
