Our brains may be tailored for bilingualism, new research reports. According to the findings, the neural centers that are tasked with combining words together into larger sentences don’t ‘see’ different languages, instead treating them as if they belong to a single one.

The same pathways that combine words from a single language also do the work of combining words from two different languages in the brain, according to the paper. In the brains of bilingual people, the authors report, this allows for a seamless transition in comprehending two or more languages. Our brains simply don’t register a switch between languages, they explain.

The findings are directly relevant to bilingual people, as it allows us a glimpse into how and why they often mix and match words from different languages into the same sentences. However, they are also broadly relevant to people in general, as it helps us better understand how our brains process words and meaning.

Speaking in tongues

“Our brains are capable of engaging in multiple languages,” explains Sarah Phillips, a New York University doctoral candidate and the lead author of the paper. “Languages may differ in what sounds they use and how they organize words to form sentences. However, all languages involve the process of combining words to express complex thoughts.”

“Bilinguals show a fascinating version of this process — their brains readily combine words from different languages together, much like when combining words from the same language,” adds Liina Pylkkänen, a professor in NYU’s Department of Linguistics and Department of Psychology and the senior author of the paper.

Bilingualism and multilingualism are widespread around the world. In the USA alone, according to data from the U.S. Census, roughly 60 million people (just under 1 in 5 people) speak two or more languages. Despite this, the neurological mechanisms that allow us to understand and use more than a single language are still poorly understood.

The specific habit of bilinguals to mix words from their two languages together into single sentences during conversation was of particular interest to the authors of this paper. In order to find out, the duo set out to test whether bilinguals use the same neural pathways to understand mixed-language expressions as they do to understand single-language expressions.

For the study, they worked with Korean/English bilinguals. The participants were asked to look at a series of word combinations and pictures on a computer screen. These words either formed a meaningful two-word sentence or pairs of verbs that didn’t have any meaning, such as “jump melt” for example. Some of these pairings had two words from a single language, while others used one word from English and another from Korean. This was meant to simulate mixed-language conversations.

Participants then had to indicate whether the pictures matched the words that preceded them.

Their brain activity was measured during the experiment using magnetoencephalography (MEG), which records neural activity by measuring the magnetic fields generated in the brain when electrical currents are fired off from neurons.

The data showed that bilinguals used the same neural mechanisms to interpret mixed-language expressions as they did to interpret single-language expressions. More specifically, activity in their left anterior temporal lobe, a brain region known for playing a part in combining meaning from multiple words, didn’t show any differences when interpreting single- or mixed-language expressions. This was the region that actually combined the meanings of the two words participants were reading, as long as they did combine together into a meaningful whole.

All in all, the authors explain, these findings suggest that the mechanisms tasked with combining words in our brains are ‘blind’ to language. They function just as effectively, and in the same way, when putting together words from a single language or multiple ones.

“Earlier studies have examined how our brains can interpret an infinite number of expressions within a single language,” Phillips concludes. “This research shows that bilingual brains can, with striking ease, interpret complex expressions containing words from different languages.”

The research was carried out with bilingual people, for the obvious limitation that non-bilinguals only understand a single language. While the findings should be broadly-applicable, there is still a question of cause and effect here. Is the neural behavior described in this paper a mechanism that’s present in all of our brains? Or is it something that happens specifically because bilinguals have learned and become comfortable with using multiple languages? Further research will be needed to answer these questions.

The paper “Composition within and between Languages in the Bilingual Mind: MEG Evidence from Korean/English Bilinguals” has been published in the journal eNeuro.