4/10: Neurolinguistics and language learning

If you've taken part in CLS events or take language classes, you probably believe there is a benefit to studying languages. We discussed how studying a second language can have tangible benefits in life, like helping with a job search, or increasing empathy toward other cultures and individuals. But research has also suggested that language learning can have even more tangible effects than that: language can alter the very structures of our minds. 

Neurolinguistics is the branch of linguistics that studies the relationship between language use and the actual structure of the brain. Before the 20th and 21st centuries, the impact of language on the human brain could only be studied by analyzing the language produced by speakers, which is only so helpful. But from the 1970s onward, advanced imaging of the brain, like CT scans or MRIs, has allowed neuroscientists and neurolinguists to look directly at what is inside of our heads. This type of research is especially important for understanding and treating patients of traumatic brain injury, if specific symptoms or loss of functioning can be connected to specific areas that were damaged.

While both sides of the brain are involved in language processing and production, neuroscientists tend to believe that the left hemisphere is dominant for language function. (Recent research has also suggested that the right hemisphere can help the brain recover certain aspects of language functioning after a stroke in the left hemisphere.) Language is one of the most visible and important parts of cognition, because it enables us to communicate meaningfully with other humans. But there are about 7000 languages in the world, which raises the question: Are all languages processed by the brain in the same way? 

Past research has shown that the human brain adapts differently to learning second languages, depending on the learner's original native language. For example, Chinese speakers who learn to read English can usually use the same patterns of brain activity - typically recognizing entire words as units - that they use to read in Chinese. However, English speakers who learn Chinese typically have to develop new connections to facilitate this type of reading, rather than relying on the connections they use to read English, which are based on phonemic awareness, or sounding out, which cannot be used to read Chinese characters. 

A recent study, though, has shown more than just the effect of a second language on building new connectivity in the brain; it suggests that the brain's structure for language functioning as a whole is actually shaped by the speaker's native language. Researchers took special MRIs of the participants that can show the depth of connection between regions of the brain. Higher levels of connectivity form pathways that can be used for processing. The results showed that native speakers of German had increased connectivity within the left hemisphere, while native Arabic speakers showed increased connectivity between their left and right hemispheres.

German has a complicated syntax or word order, and syntactic processing is mostly in the left hemisphere. Meanwhile, Arabic is semantically complex, so the meaning of individual words can be  relatively more difficult to determine. Both factors seem to correspond with the results found from the brain images. So the study seems to show that connections in the brain differ based on native language—and these connections correspond to structural properties of each language.

For bilingual individuals, neuroimaging has demonstrated that bilingualism can "enhance attention and sensitivity to sounds" and increase processing efficiency. Even for late learners, these benefits are possible. Contrary to beliefs that bilingualism from a young age might hurt a child's ability to learn to speak or read language in general, imaging has shown it actually allows them to be more flexible and make more connections with the existing neural structure. These connections can have general cognitive benefits as well, not just confined to language. 

Of course, there are also other factors beyond the linguistic structure of a language that influence the connections in our brain—like gesturing, or the cultural nuances of a conversation. But these factors are also intimately intertwined with the language itself; it will take rigorous research to untangle them and determine exactly how the brain structure changes based on these factors.

But for second language learners, these results about native and second languages having an influence on brain structure still seem to generally reaffirm the intuition that language learning has important benefits. Bilingualism, whether learned in childhood or later, can make the brain more flexible, creating different sets of connections and the ability to adjust to new situations. As one professor put it: "Learning a new language changes, and even optimizes, how you use what you already have.