How language shapes the brain
From the moment sound waves enter your ear and become neural impulses, your brain executes this rapid-fire series of events that few of us are ever aware of, but without which we'd be unable to communicate.
For bilingual speakers, this process involves both languages -- from the first syllable they hear, their brain is working to identify the word, and the listener's brain begins identifying any words, in either language, that could fit the sounds as they arrive in sequence. Having to distinguish between two languages can be tricky in some situations, but the brain's executive functions, especially the attention and inhibition processes, are strengthened through this process, ultimately making bilingual speakers better at switching between two tasks or handling tasks that require conflict management.
How language shapes your brain depends in part on when you learn another language. For example, Broca's area differs between young language learners and older language learners. If a child grows up bilingual, the same region in Broca's area handles the processing of both languages. However, if you learn a language after adolescence, a separate area develops for the second language near the area used for your native tongue. Despite the difference in brain structure, language learners both old and young gain the benefits of speaking multiple languages.
Because the language centers in the brain are so flexible, learning a second language can develop new areas of your mind and strengthen your brain's natural ability to focus, entertain multiple possibilities, and process information.
Just as you exercise your body to keep your heart healthy and muscles strong, exercising your mind can sharpen your decision-making and improve your communication skills. So if you only speak one language or haven't spoken your second language since high school, now's the time to get learning.
Doubling down on a pair of languages rather than just one does take extra work, but it’s work young children are generally not aware they’re doing. Bilingual people of all ages are continually addressing what research psychologist Ellen Bialystok of Toronto’s York University calls the dog-chien dilemma, encountering an object, action or concept and instantaneously toggling between two different words to describe it. Such nimble decisionmaking ought to improve on-the-fly problem solving, and studies show that it does. Sean Lynch, headmaster of the LFNY, previously worked in a multilingual school in France in which all of the students spoke French and at least one of 12 other languages, including Japanese, Russian, Italian and Spanish. As is often the case with well-endowed schools, the students, on average, outperformed their age peers academically, and it’s impossible to determine how much of that is due to native skill and how much to the fact that they simply have access to better teachers, books and other resources. Still, Lynch observed that these students seemed to show a greater facility with skills that relied on interpreting symbolic representations, such as math or music. Lynch also believes — albeit based primarily on his own observations — that multilingual kids may exhibit social empathy sooner than children who grow up speaking only one language, which makes developmental sense. The theory of mind — understanding that what’s in your head is not the same as what’s in other people’s heads — does not emerge in children until they’re about 3 years old. Prior to that, they assume that if, say, they know a secret you probably do too. There’s a kind of primal narcissism in this — a belief that their worldview is the universal one. Once they learn that’s not the case, self-centeredness falls away — at least a little — and the long process of true socialization begins. There’s nothing that accelerates the acquisition of that kind of other-awareness like the realization that even the very words you use to label the things in your world — dog, tree, banana— are not the same ones everyone uses. Preliminary imaging work suggests that the roots of this behavior may even be visible in the brain. Some studies, for example, have shown a thickening of the cortex in two brain regions — most importantly the left inferior parietal, which helps code for language and gesturing. Bialystok is not entirely sold on these studies, since she would expect the greatest differences to be in the frontal lobes, where higher functions such as planning, decisionmaking and other aspects of what’s known as executive control take place. Some of her own work has found an increase in white matter — the fatty sheathing that insulates nerves and improves their ability to communicate — in the frontal regions of bilinguals, suggesting denser signaling and complexity of functions in these areas. “Structural differences are where the new science is really unfolding,” she says. “That work will reveal a lot.” In one study, bilinguals experienced the onset of age-related dementia 4.1 years later than monolinguals, and full-blown Alzheimer’s 5.1 years later. “One school of thought says that any cognitive reserve — education, multilingualism, even playing Sudoku puzzles — strengthens the brain and helps it resist disease,” says Bialystok. “The other says that the brains of multilinguals experience the same level of disease as those of monolinguals, but they cope with it better. They function at a higher level than they would otherwise be able to function.”
In another 2013 study, this one from the University of Kentucky, bilingual and monolingual people in the 60- to 68-year-old age group underwent brain scans while performing a cognitive task that required them to switch back and forth among several different ideas. Both groups performed the task accurately, but bilinguals were faster as well as more metabolically economical in executing the cognitive mission, using less energy in the frontal cortex than the monolinguals.
The very fact that something as simple as working with puzzles or having once got a good education can improve brain function does prove that multilingualism is not the only path to staying cognitively healthy in your dotage. And plenty of monolinguals do perfectly well at acquiring empathy and social skills early in life. Still, there are roughly 6,500 spoken languages in the world. There must be a reason our brains come factory-loaded to learn more than just one.