Most people learn a language or two in their lifetime. But Vaughn Smith, a 47-year-old carpet cleaner from Washington, DC, speaks 24. Smith is a hyperpolyglot — a rare individual who speaks more than 10 languages.
In a new brain imaging study, researchers have peered inside the minds of polyglots like Smith to find out how language-specific regions in their brain respond to hearing different languages. Familiar languages elicited a stronger response than unfamiliar ones, they found, with one important exception: native languages, which elicited relatively little brain activity. This, the authors say, suggests that the languages we learn early in life are special.
This study “contributes to our understanding of how our brain learns new things,” says Augusto Buchweitz, a cognitive neuroscientist at the University of Connecticut, Storrs, who was not involved in the work. “The sooner you learn something, the more your brain [adapts] and likely uses fewer resources.”
Scientists have largely ignored what’s going on in the brains of polyglots — people who speak more than five languages — says Ev Fedorenko, a cognitive neuroscientist at the Massachusetts Institute of Technology who led the new study. “There’s a ton of work on people whose language systems aren’t working properly,” she says, but almost none on people with advanced language skills. That’s partly because they make up just 1% of the world’s people, making it difficult to find enough participants for research.
However, studying this group can help linguists understand the human “language network,” a series of specialized brain areas located in the left frontal and temporal lobes. These areas help people with the most fundamental aspect of language comprehension: according to Fedorenko, the association of sounds and meanings.
To find out how the brain processes five or more languages, Fedorenko teamed up with Saima Malik-Moraleda – a Harvard PhD student and polyglot herself – and a team of other researchers. They scanned the brains of 25 polyglots, 16 of whom were hyperpolyglots, including one who spoke more than 50 different languages. They used a brain imaging technique called functional magnetic resonance imaging (fMRI), which measures blood flow in the brain, to map these language networks.
Inside the fMRI machine, the polyglots listened to a series of 16-second recordings in one of eight different languages. Each recording was selected from a random portion of the Bible or Alice in Wonderland, which they or other groups had previously translated into 25 and 46 languages, respectively. The eight languages included each participant’s native language, three others they learned later in life, and four unfamiliar languages. Two of the unfamiliar languages were closely related to the participant’s native language – for example, Spanish for a native Italian speaker. The other two unknown languages come from unrelated language families.
The researchers found that when participants listened to any of the nine languages, blood always rushed to the same brain regions. Instead of using different parts of the brain, the participants’ brains appeared to use the same basic network as monolinguals to try to make sense of the sounds, regardless of what language they were hearing.
Activity in the brain’s language networks fluctuated depending on how well participants understood a language. The more familiar the language, the greater the response. Brain activity particularly accelerated when participants listened to unfamiliar languages that were closely related to those they knew well. This could have happened as brain areas were working overtime to decipher the meanings based on similarities between languages.
There was one exception to the rule: When participants listened to their native language, their speech networks were actually quieter than when they heard other familiar languages, the researchers reported last month in a preprint uploaded to the non-peer-reviewed server bioRxiv became . This trend continued even when participants were fluent in their other familiar languages, suggesting that less brain power is required to process languages learned early in life.
That could be because expertise reduces the amount of brain power needed to complete a task, the researchers note. Previous studies have shown similar results with bird watchers and used car salespeople who were asked to talk about known and unfamiliar topics. “When you become a specialist in something, you use fewer resources,” says Malik-Moraleda. The study suggests that peak cognitive performance is more likely when learned at a young age.
No previous study has examined so many polyglots. “It’s a very important work on polyglots,” says Buchweitz. However, as the results are purely descriptive, any conclusions about the work are still preliminary.
Many polyglots and hyperpolyglots deny any talent for language learning, says Fedorenko. Still, she wants to examine how polyglot brains pull off a trick that so many others find nearly impossible, and whether they have an innate talent or just an interest or opportunity. Understanding what a brain needs to learn languages could one day lead to better tools to help people learn languages again more easily after a stroke or brain damage.