Brains are naturally wired to be bilingual


In this interview, News-Medical tells Sarah Phillips about new research on how bilingual brains process different languages, and how the same neural mechanism is used for each when interpreting expressions in multiple languages.

Please introduce yourself and tell us about your background in neuroscience.

My name is Sarah Phillips and I am currently a PhD student in Linguistics. student at New York University. Before coming to NYU, I had no experience in neuroscience research. I studied code-switching – the alternation between languages ​​in speech – through sociolinguistic and theoretical perspectives. This has been and continues to be very motivated by my experiences growing up as a bilingual English Korean and African American.

It wasn’t until I was working for an academic editor that I was exposed to what neuroscientists were saying about the bilingual mind, which seemed more focused on how bilingualism can affect cognition more broadly. I felt there was a gap in the understanding of how bilinguals deal with languages, so that’s where my journey in neuroscience began.

How are languages ​​processed by the brain?

I think the domain recognizes the number of regions of the brain used to process language, with each region harboring mechanisms responsible for specific tasks. Liina Pylkkänen, lead author of the article and my advisor, has systematically studied the role of the left anterior temporal lobe in the way we derive meanings by composing words together. This is just one of the many tasks involved in language processing.

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What did you find about the brain combining words from different languages, and would that teach us about the brain and bilingualism?

My work extends much of what we know about how we combine words from the same language to what many bilinguals do, which is also combining words from different languages.

We found that bilinguals recruited the left anterior temporal lobe to combine words from the same language as well as from different languages ​​without exhibiting language switching effects. I think this tells us that monolinguals and bilinguals use similar neural mechanisms to derive meanings through composition.

How did you study this?

We used magnetoencephalography (MEG) to record the brain activity of Korean / English bilinguals when presented with two words, followed by a picture. The two words varied in three ways: they varied according to whether or not they were composable (“the ice cubes melt” versus “the melted ones jump”); they varied depending on whether the words were in English or Korean (“고드름 melt” vs “뛰어 melt”); they varied depending on whether Korean words were in Hangul (the standard writing system for Korean) or the Roman alphabet (which is the same set of letters used in English).

After seeing the two words, our participants saw a picture and were asked to rate whether what they were reading matched the picture they had seen.

What is magnetoencephalography (MEG) and how was it used in your study?

I should start by saying that the neurons in our brains emit electrical signals when they communicate with each other. These signals generate an electric current and the electric currents generate electromagnetic fields.

MEG is a technique that records changes in electromagnetic fields produced by neuronal discharges in our brain. We used this technique to identify when, in milliseconds, particular brain regions activate in response to two words presented to participants.

What parts of the brain were activated during the bilingualism tests?

While several regions were activated in response to multilingual expressions, the timing of when they were activated is important in this study. If the words are presented in a combinatorial context (“melt” presented after “ice cubes”), we would expect them to cause an increase in activity in the left anterior temporal lobe at about 200 msec compared to the same words. presented in a non-combinatorial context. context (“melt” presented after “jump”).

We saw this effect in our bilingual participants, even when the words changed language. While the left anterior temporal lobe did not show sensitivity to the change in language or writing system during this combinatorial stage of treatment, we observed robust effects in several regions caused by a match between the change in language and the change of writing system.

The left anterior temporal lobe, the left inferior frontal gyrus (better known as the “Broca’s zone”), the anterior cingulate cortex, and the ventromedial prefrontal cortex all responded more each time the language change corresponded to changes in language. writing systems, but at different times. This leaves open the question of how bilingualism can affect all of these regions.

Temporal lobe

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If the same neural mechanism is used to interpret expressions in multiple languages ​​and to interpret expressions in only one language, how does the brain separate the different languages?

Current ideas about how bilinguals store words in their lexicons (which one can imagine to be a mental dictionary) suggest that we maintain linguistic distinctions at the level of perception (i.e. how words ring or are written).

I think the interaction effects between language membership and writing systems speak to this, but I don’t know how we keep languages ​​separated at the level of perception based on the results of this project.

Why is it important to understand the nature of bi- and multilingualism?

Many, if not most, people around the world engage in more than one language on a daily basis, and yet our current understanding of how our brains process language is limited to those who engage in just one language.

I believe that the development of more linguistically inclusive language processing models is essential for the success of our models when applied in clinical settings.

What impacts could this research have when applied to today’s society?

One of the main points to remember is that bilingual behavior should not be viewed as deviant or bad because it does not look like monolingual behavior.

Having said that, I think this project serves as a starting point for understanding typical bilingual behaviors so that bilinguals are not mistakenly perceived as poor language users or, worse yet, misdiagnosed for having a treatment deficit. language.

What is the next step in this research?

Languages ​​can differ significantly in how they structure words together into sentences (syntax), but this study used stimuli that kept the syntax consistent within each type of stimulus. I did this to make sure the switching effects weren’t confused by syntactic differences.

However, I think it’s important to see what happens when bilinguals switch languages ​​in expressions where the two languages ​​are syntactically different, as this is a commonly observed phenomenon.

Where can readers find more information?

Readers can access the document using the following link: https://doi.org/10.1523/ENEURO.0084-21.2021

About Sarah Phillips

Sarah F. Phillips is currently a doctoral student in linguistics. Student at New York University. His work mainly focuses on bilingual language processing and bilingual language development, using both neuroimaging and behavioral methods.Sarah phillips

You can find more information about Sarah on her website: www.sarahfphillips.com


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