The brain uses a shared mechanism for combining words from a single language and for combining words from two different languages, a team of neuroscientists from NYU New York (NYU) and NYU Abu Dhabi (NYUAD) has discovered. The findings, which appear in the journal eNeuro, indicate that language switching is natural for those who are bilingual because the brain has a mechanism that does not detect that the language has switched, allowing for a seamless transition in comprehending more than one language at once.
“Although languages differ in what sounds they use and how they organize words to form sentences, our research demonstrates that all languages combine words to express complex thoughts. Bilinguals demonstrate a fascinating version of this process in that their brains readily combine words from different languages together, much like when combining words from the same language."
A high proportion of UAE residents and citizens use two or more languages. However, despite the widespread nature of bi- and multilingualism, the neurological mechanisms used to understand and produce more than one language are not well understood, raising questions about how the brain functions in such exchanges.
To better understand these processes, Pylkkänen and the research team explored whether bilinguals interpret these mixed-language expressions using the same mechanisms as when comprehending single-language expressions or, alternatively, if understanding mixed-language expressions engages the brain in a unique way.
To test this, the scientists measured the neural activity of bilingual speakers, with the study’s subjects viewing a series of word combinations and pictures on a computer screen. They then had to indicate whether the picture matched the preceding words. The words either formed a two-word sentence or were simply a pair of verbs that did not combine with each other into a meaningful phrase (e.g., “icicles melt” vs. “jump melt”). In some instances, the two words came from a single language while in others both languages were used, with the latter mimicking mixed-language conversations.
To measure the study subjects’ brain activity during these experiments, the researchers deployed magnetoencephalography (MEG), a technique that maps neural activity by recording magnetic fields generated by the electrical currents produced by our brains. The recordings showed that bilinguals used the same neural mechanism in interpreting mixed-language expressions as they did while interpreting single-language expressions.
Specifically, the brain’s left anterior temporal lobe, a brain region well-studied for its role in combining the meanings of multiple words, was insensitive to whether the words it received were from the same language or from different languages.
These findings suggest that language switching is natural for bilinguals because the brain has a combinatory mechanism that does not “see” that the language has switched, and can easily interpret complex expressions containing words from different languages.