The Health Benefits of Bilingualism

I can tell you the short version of this story, but first, it’s important to understand that everything we do changes the way we think to some degree. Brains are always changing, and this is a normal, ongoing part of our cognitive life.

Now, if we spend a lot of our time or energy doing a specific kind of thing, then there may be very specific effects of that. Using language is one of the things we do more than anything else in our lives. We use languages all our waking hours and maybe during some of our nonwaking hours, too. So if using languages is different for people who use more than one language, then that’s a case where we might indeed find that our brains and minds may be different.

What happens when you use a language? The crucial piece here is something that’s very surprising, and it’s how your brain manages two languages. You probably think that the best way to build a brain that could handle two languages would be to put a sort of switch mechanism in. But that’s not how it works. If you are bilingual or trilingual, then all the languages that you speak fluently are always active. They never turn off. There’s no switch. There is always the need to select the language you need in the moment, so that you don’t have interference.

Monolinguals don’t have that problem. They just go ahead and speak and choose words from the language they’re using. But for bilinguals, there’s a constant ongoing need to not only choose what you want to say but select the language you’re going to say it in.

The final piece of this story is that over many years, this need for selection changes the way bilingual brains pay attention and select—even if it’s not selecting languages. Even if it’s something completely different. Bilingual brains learn how to select and pay attention much faster, more efficiently, and using fewer resources than monolingual brains. That can turn out to be a big deal in the long term.

We see it in the first year of life even before children speak: Infants in bilingual environments pay attention to their environment differently. It is kind of interesting but not terribly important.

Where children need to pay attention to one kind of thing and ignore information that’s distracting or irrelevant—bilingual children can do those things better than monolingual children. They can do them faster.

In adulthood, the selection processes can also lead to better performance on some tasks. You can solve a little selection problem faster or make fewer errors on a task that requires selection. That really doesn’t have big payoffs. The big potential payoff is: Over a lifetime of using these different processes for selecting and attending, bilingual brains are able to do those problems with less effort.

In older age, those selection processes begin to slow down, making it hard for older adults to do things like multitask, because they need to use the very effortful front part of their brain to do the multitasking. Our research shows that bilinguals can do those problems—multitasking and so on—without having to call in the very effortful front part of their brain, leaving open resources to help out when needed. For that reason, we find a significant delay in cognitive decline in bilingual older adults, up to and including the point of dementia.

There’s now evidence from many countries in the world showing that the average onset of dementia in bilinguals is about four years later than in monolinguals. Not because they don’t get dementia; they do. But because once they have dementia, their brains are able to function in spite of it for a longer time. They can carry on even when dementia is affecting their brains because their brains have these resources to help them out and maintain higher levels of cognition.

The connection is about looking at the brain at the point of diagnosis and not about the absence of Alzheimer’s in bilinguals entirely. Clinicians, neurologists, psychiatrists, even general practitioners will make a diagnosis of Alzheimer’s largely on the basis of a person’s functional level of performance. When they fall below a particular cognitive threshold, they get diagnosed as having either mild cognitive impairment or dementia or Alzheimer’s.

Symptoms generally show up at a later stage of neurodegeneration in bilinguals. The bilingual brain is able to compensate and continue to function kind of normally, even though the neuropathology is already in their brains.

That’s important because there’s no cure for Alzheimer’s. The medications are not very effective, so finding a way for people to function normally in the early stages of the disease can make a big difference. Postponing symptoms means postponing the need for the health care system, medication, hospitals.

This is a really important question, and it’s a hard one to answer. Bilingualism is not what we call a categorical variable: You’re not monolingual or bilingual as you are with almost everything else that psychologists measure—old or young, male or female, twenty-five or fifty years old.

Bilingualism is a complex continuum of experiences. That means that this is difficult research to do, because you have to figure out what criteria you mean for bilingual. One simple way of answering the question is bilingualism means you have the capacity to carry on a conversation with greater or lesser fluency in more than one language.

The way I like to answer the question is by saying the more, the better. If you have been bilingual for a longer period of your life, then the effects are larger than the effects for people who are more recently bilingual. If you use your second language more often in your life, then the effects are larger. If you have a higher proficiency in the second language…and so on.

The bottom line is: These are experience-dependent effects. The more experience you have, the larger the effects. The more, the better.

I don’t think it matters. We’ve looked at things in our research, like given that bilingualism is such an individual experience, and there are so many varieties of bilingual experience, what part of bilingual experience is most important in creating these effects? If you put it that way, we’re finding the most important aspect of your unique bilingual experience is just how much you use the language. Quantity of usage.

The more you use a language, the more you’re engaging these processes, and the more you’re contributing to the brain-rewiring we associate with these protective effects.

People often say, “Well, I have no ability to learn a language, so I can’t become bilingual, and I can’t learn a second language—end of story, goodbye.” I hear this a lot.

Everything that we do, as individuals, we have different amounts of ability to do. There are things that I desperately wish I could do, but I can’t. It’s just not part of my skill set. Now, that doesn’t mean you can’t do them at all. It just means that we’re different from each other in how easy some things are. Some people have a tremendous talent for music or dance or mathematics. We accept that we’re all different in that way.

Language, like everything else, is something that appears in some individuals at a higher aptitude than others. But that’s not an excuse to say you can’t possibly learn a language. It’s a matter of attention, and effort, and practice, and all the other stuff. Everybody learned their first language, so even though we don’t all have a talent for learning more languages, it’s still possible to learn to some point of proficiency. We can make progress.

It’s because the mother tongue is far less sacred than you might think. A couple of comments on that example, because there’s a lot to unpack:

First, why is she losing Russian vocabulary? Because she doesn’t choose it every day. I mean, it makes perfect sense, right? She’s not using Russian, so she’s forgetting it because language is, among other things, a skill. If you’re a brilliant concert pianist and you’ve spent much of your life playing a Rachmaninoff piano concerto, and then some years go by and you don’t play it, you’re not going to play it as well. You don’t get all upset thinking you’ve lost your ability. You just say, “Well, yeah, I haven’t been practicing. I’m going to get it back.” There is nothing magical about language. If you’re not using a particular language, you’re going to get less fluent in it.

The second point is that there’s this mythology that a bilingual person has either a) two equally fluent languages or b) a main language that’s their primary language and then a secondary one. Neither scenario is the case, because which language a bilingual considers primary can ebb and flow across the life span.

There are many cases of people who have a particular first language, their mother tongue. It’s their dominant language. Then life changes in various ways that life does, and that language becomes their less dominant language and another language takes a more dominant role, and so on. These are very fluid relationships.

One other point, even for people who have a dominant first language but have a particular experience that is always conducted in the other language, they will be more capable of handling that experience in the less dominant language. For example, a colleague of mine is a native speaker of Spanish and spent his entire life speaking Spanish. He’s retired now, but he always worked in English. Some years ago, he was asked to deliver a series of lectures in Spanish. He almost couldn’t do it, because he never talked about his work in Spanish. So which language you’re able to do something in more easily—it’s very specific to which language you actually do that thing in.

Probably. I think literacy activities in a language are very important, but we know less about what those effects are. We’ve got to figure out exactly how that works.

There’s an interesting, but so far untested, opportunity with all of these language-learning apps. It’s now relatively accessible for people to at least try to learn another language. Some of them are very engaging, and they don’t take a lot of your time. If there’s some kind of benefit, then that would really be a terrific way of increasing overall levels of bilingualism. We don’t know, at this point, if using those apps has any long-term effect. We are going to do a study on it.