The brain uses a shared mechanism for combining words from a single language as well as ones from two different languages, a team of neuroscientists has discovered. The findings indicate that switching languages comes naturally to 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 the comprehension of more than one language at once.
“Our brains are capable of engaging in multiple languages,” explains Sarah Phillips, an NYU linguistics doctoral candidate and the lead author of the paper, “Composition within and between Languages in the Bilingual Mind,” which appears in the journal eNeuro. “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, much like when combining words from the same language,” adds Liina Pylkkänen, the codirector of the Neuroscience of Language Lab at NYU Abu Dhabi, a professor in NYU’s linguistics and psychology departments, and the paper’s senior author.
An estimated 60 million people in the United States use at least two languages, according to the US Census. Across the globe, the majority of people know more than one language. Indeed, many countries have more than one official national language.
Unsurprisingly, in today’s highly globalized world, bilingualism provides a variety of meaningful social and practical advantages. People using multiple languages can converse with a wider array of people, and they can also more readily connect across cultures and adjust to new situations. At NYU, students studying away benefit from exploring new places and having new experiences as members of the University’s global network. But they also have the opportunity to immerse themselves in a different language, deepening their experience and sharpening their minds.
Yet, despite the domestic and international widespread nature and evident benefits of bi- and multilingualism, the neurological mechanisms used to understand and produce more than one language are not well understood. This terrain is an intriguing one; bilinguals often mix their two languages together as they converse with one another, raising questions about how the brain functions in such exchanges.
Phillips and Pylkkänen sought to better understand these processes. They 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 Korean and English bilinguals. The study’s subjects viewed a series of word combinations and pictures on a computer screen. Then, they indicated whether or not 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 into a meaningful phrase (such as, “icicles melt” versus “jump melt”). In some instances, the two words came from a single language (Korean or English) while others used both languages, with the latter mimicking mixed-language conversations.
In order to measure the study subjects’ brain activity during these experiments, the researchers deployed magnetoencephalography. The technique maps neural activity by recording magnetic fields generated by the electrical currents produced by our brains.
The recordings showed that Korean and English bilinguals, in interpreting mixed-language expressions, used the same neural mechanism 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. This region, then, proceeded to assign complex meaning to two related words regardless of whether they shared a language.
These findings suggest that language switching is natural for bilinguals because the brain has a combinatory mechanism that does not “sense” the language has switched. “Earlier studies have examined how our brains can interpret an infinite number of expressions within a single language,” Phillips observes. “This research shows bilingual brains can, with striking ease, interpret complex expressions containing words from different languages.”
You can watch Phillips discussing her research on bilingual speakers in this NYU-produced video (credit: NYU, courtesy of Kate Lord).
Content repurposed with permission from NYU News