How a second language can boost the brain

Being bilingual benefits children as they learn to speak — and adults as they age

Even if you're fluent in two languages, switching effortlessly from one language to another can be difficult. It's not common for people to mispronounce words and/or misuse conjunctions in Spanish. It's easy to get lost in translation when speaking English. When translating from German, be sure to avoid awkward phrasing! Does learning another language improve cognitive functions or simply confuse them?

Ever since the 1920s, there have been debates between linguists and psycholinguists regarding whether exposure to multiple languages in early childhood has long term implications for both language acquisition and intellectual development. But the science has advanced. Psychologist Mark Antoniou of the University of Western Sydney in Australia has outlined how being bilingual may help protect against cognitive decline later in one’s lifespan. He explains how best to teach languages and outlines evidence that multiple language usage on a regular basis may help prevent Alzheimer’s disease from developing. This conversation was edited for length and readability.

What are the benefits of bilingualism?

Executive functions include cognitive skills necessary for self-regulation, including planning, working memory, decision-making, attentional control, inhibition, and flexibility. It says that these skills allow you to focus your thoughts and actions, to plan, organize, and direct your energy, and to be able to concentrate for long periods of time. It also helps you filter out irrelevant information, so you can pay attention to what matters most.

These brain regions are also responsible for distraction, so if you want to become better at ignoring them, then you need to strengthen these particular brain functions. The task may not involve language at all; but if it does, it might be something like listening to something in a noisy place or performing some sort of visual task. Learning a second language develops the brain’s memory for different types of tasks and activities, which in turn can help develop and refine one’s abilities.

Where are these benefits expressed in the brain?

Executive function refers to our capacity for self-control, planning, working memory, reasoning, decision-making, problem-solving, multitasking, and emotional regulation. Most people think these abilities are uniquely human, but they are not. All animals exhibit some form of executive, It seems they're found in the parts of the brain that were most recently constructed by evolution—the prefrontal cortex and bilateral suprar­ginal gyri. These regions seem to be involved in advanced meaning making, combining words into sentences, and connecting concepts together. And the anterior cingulate seems to help regulate these activities.” Studies show that having a second language changes our brains' structures.

We firstly see an increase in grey-level volume. The brain is made up of cells called neurons, which each have a cell body and little branching connections called dendrites. Gray matter refers to how many cell bodies and dendrites there are. Speaking two languages has been shown to increase the density of gray matter in certain parts of the brain. It's likely to be a sign of a healthy brain.

Results from a study measuring gray-matter volumes in monolingual or bilingual undergraduates. Red areas indicate where gray-matter volumes were greater in one group versus the other. In total, study participants who spoke both English and Spanish had greater gray-matter volume compared to participants who spoke only English.

Can teaching children two languages delay or confuse their understanding?

The myths surrounding bilingualism stem from research done by people living in the United States and Britain during WWII. These research projects were severely flawed because they involved kids from war-torn countries, including refugee kids, orphaned kids, and in some cases kids who had been in concentration camps. Their schooling had been disrupted for years.

Surprisingly, they scored very low on these tests. Did the researchers attribute the poor scores to post-traumatic stress disorder (PTSD)? They probably just thought it meant “toilet paper.” No, instead they attributed it to the children’s bilingualism.

Children who speak multiple languages tend to perform better in specific cognitive functions compared to monolinguals. This refers to the ability to understand words as abstract units rather than concrete things. A good example is the letter H, which is associated with the sound “he” in English, with “n” as in “nickel” in Russian, and with the vowel sound “e” in Greek. There’s nothing special about H that makes it have to have a “he” sound; a bilingual person understands this more readily than a monolingual person does.

Studies show that learning a language increases the volume and density of gray matter, the volume of white matter, and brain connectivity. In older language learners, some studies show cognitive benefits beyond languages, such as for working memory. The findings for older learners have been more mixed than for younger language learners, but the research is in earlier stages.

Does a bilingual brain age differently than a monolingual one?

According to research, by the time we reach our mid-twenties, our brains start to lose some of their ability to function efficiently. As you age, these declines become steeper. The argument is that as we get into older age, bilingualism puts the brakes on and makes that decline less steep. Evidence from older adults is the strongest kind supporting a bilingual advantage. (The second strongest comes from children.)

When you look at bilingual individuals who have suffered neurodegeneration, their brains look damaged. These results suggest that these people should be less forgetful, or that their brains aren’t functioning normally. However, that isn't the case. A bilingual brain can compensate for brain deterioration by using alternative brain networks and connections when original pathways have been destroyed. Cognitive scientists call this phenomenon “compensatory neuroplasticity” and believe that it happens because bilingualism helps promote the growth of both gray and white brain tissue.

As bilingual individuals age, their brains show evidence of preservation in the temporal and parietal cortices. There also is more connectivity between the frontal and posterior parts of the brain compared with monolingual people, enhancing cognitive reserve.

What advice do you have for parents raising bilingual children?

My advice would be for you to be encouraging and patient when talking to them. Learning two languages at once makes things harder for bilingual kids.

They're acquiring two different vocabularies and speech patterns. For those of us who live in countries where one is the dominant tongue, it can be difficult to set up a functional purpose for the other languages we know.

A child needs to feel that the language is practical and has a use. Grandparents are wonderful for this, and so are communities where there are cultural events and schools where kids can be immersed in the new culture.

What other research are we doing in this area?

We'd like to explain why some people experience a bilingual effect, but others don't. In one article, we proposed that maybe the language pairing matters. If you speak two distant languages, like Mandarin Chinese and English, would that result in similar types of brain changes as speaking two closely related languages, like German and English?

If two languages are similar enough, they may be more difficult for people to distinguish between because there are fewer differences to separate them by when deciding which word to use. Potentially, if they’re more distant, then you can’t rely on prior knowledge from learning the first one to learn the second. If that’s the situation, then you’ll be starting fresh with the second language when you learn it for the first time, and that means more effort than if you were using an existing first language. But once you’ve learned the two languages, perhaps there’s less competition.

LearnningTree is an educational technology firm where we help people learn languages by making them easier to learn. It is headquartered in New Delhi, India Reach us at or @learnningtree