Bilingualism is an advantageous ability in ways that go beyond simply being able to communicate with others. It literally changes the brain, inducing heightened neuroplasticity and protecting against cognitive decline. New research also suggests a little-understood brain region uniquely adapts to different written languages—a finding that sheds light on the mysteries of language recognition.
In a study published on April 5 in the journal Science Advances, researchers examined how bilinguals process their respective languages in written form. They discovered that a part of the brain called the Visual Word Form Area (VWFA) activates differently for English-Chinese speakers compared to English-French speakers.
While most research on bilingualism compares people who speak two languages to those who just speak one, this study compares bilinguals of different languages and writing systems. Scientists analyzed the brains of people who speak English and Chinese, along with the brains of people who speak English and French. While an fMRI machine measured their brain activity, participants viewed visual stimuli like letters, faces, and houses.
In both groups, the VWFA reacted likewise when shown English or French. But when English-Chinese participants read Chinese characters, distinct areas lit up in response.
The study team, in turn, discovered clusters of neurons specific to the Chinese language in English-Chinese bilinguals. In English-French bilinguals, their brain activity was the same regardless of language stimuli. Their research further demonstrates that the brain develops in response to an individual’s unique experiences.
“My initial impression of [the study] is that it’s a real tour de force methodologically and in terms of design it’s comprehensive, thorough and ambitious,” says Dale Stevens, a York University neuroscience professor who was not part of the research. It also gives us “a more specific understanding” of the VWFA, he adds.
What is the Visual Word Form Area?
The VWFA is the region of the brain that recognizes written words. It develops when people learn to read, which builds neural pathways between the visual and language systems. Without it, people would be unable to read.
Minye Zhan, the first study author and a cognitive neuroscience researcher at NeuroSpin, a research institute in France, expected to find some neurological differences between dominant English speakers, dominant French speakers, and balanced English-French speakers. Instead, the 21 English-French bilinguals didn’t demonstrate any processing differences, despite their dominance in one language over the other.
“It’s the same system,” Zhan says. “I dug hard and didn’t see any difference. It was a very big surprise.”
Meanwhile, the brains of the ten English-Chinese speakers reacted very differently when shown Chinese characters. In this group, Chinese was the dominant language. When the researchers scanned the brains of these participants, they found distinct activity: Chinese-specific clusters of neurons in the VWFA.
How did researchers map brain activity?
Previously, pinpointing specific areas of brain activity challenged researchers. Now, high-resolution MRI machines, such as the 7-Tesla fMRI used in this study, allow for more detailed brain scans. The research team, in turn, could see that chains of neuron clusters activated when the study participants saw Chinese. Zhan describes it as “a galaxy, a constellation of areas.”
“The interesting part is that there are these word patches that process both languages, even different languages like English and Chinese,” Zhan says. “They’re so different, but they are processed in the same area, although there are specialized Chinese-only language patches in the brain.”
Interestingly, brain response to Chinese stimuli overlaps with a region that helps with facial recognition. The difference might have something to do with cognitive processing. The brain can perceive visual stimuli as a whole or in parts, and the strategy it chooses depends on the language read.
Why are there language-specific areas?
When you see a face, you don’t recognize eyes, noses, and a mouth as separate parts. Instead, you see a face as a face, a unified whole. Research has shown that native Chinese speakers process Chinese characters similarly, which have combinations of strokes and radicals. Meanwhile, part-based processing is more common in alphabetic languages, such as English and French. Individual letters, or letter combinations, are processed separately and then integrated to form a coherent word.
Another explanation has more to do with language structure. Chinese, like Japanese and some Korean, is logographic. These writing systems use characters that correspond to concepts, ideas, and words. Phonetic languages, like English and French, use characters that correspond to sounds.
Most Chinese characters give few clues as to how they are read. New learners, including Chinese children, pick up character pronunciation using Pinyin, which uses the Latin alphabet to spell out sounds of Standard Chinese characters. Meanwhile, when children study French or English, both phonetic languages with a strong connection between spelling and pronunciation, they’re encouraged to sound out words letter by letter.
Learning Chinese might place unique demands on neural pathways, resulting in different connections. Still, these explanations for the VWFA’s split are speculation for now. Researchers don’t know precisely why the brain reacts differently for English-Chinese bilinguals, just that these bilingual speakers have specialized brain activity unobserved in the English-French group.
This research wouldn’t have been possible more than a few years ago. The experiment used a high-resolution 7-Tesla fMRI scanner, which has a much stronger magnetic field that can scan brain activity in greater detail compared to previous models (a Tesla is a unit of measurement to quantify magnetic field strength). The U.S. Food and Drug Administration approved this model in 2017.
In contrast, a hospital might use a 1.5 or 3-Tesla MRI machine. And while this resolution is the standard, it doesn’t reveal the same level of detail, Zhan says.
The research raises many questions, says Zhan. Her team is interested in repeating the study with groups of participants who speak different native languages and use different alphabets. Zhan also wants to discover why these specialized patches of neurons emerge depending on what language a person can read.
“So why do those special patches come up?” she says. “That we don’t know. We just observe them. So we report first and say that it needs more research.”