Speaking and understanding another language provides mental stimulation, which keeps the brain active and agile as we age.
In fact, researchers have found that being multilingual can delay the diagnosis of dementia and slow brain aging.
Unlike, for example, music, which someone can practice for a few hours a day, the mental stimulation that language provides is “intense and constant,” said Ellen Bialystok, distinguished research professor emeritus of psychology at York University in Canada, who has studied the effects of languages on the brain for more than five decades.
Knowing more than one language—and practicing it frequently—is like constantly training your brain. Being multilingual changes brain function and structure.
“If you constantly use your brain to face difficult, interesting and stimulating challenges, your brain will be healthier,” Bialystok said. “And learning a language is hard, and that makes it worth it.”
How languages change the brain
If you know multiple languages, your brain keeps them “on” all the time, even when you’re not speaking them.
In bilingual people, there are cortical areas in the brain’s linguistic network that respond to both languages. However, within that broad area, there are specific regions that respond only to one language, explained Lucia Amoruso, deputy scientific director and leader of the language neurobiology group at the Basque Center for Cognition, Brain and Language in Spain.
While speaking or listening in one language, “the other language is also active in your brain. It’s not asleep,” said Amoruso, who noted that she needed to suppress Spanish, her native language, when responding in English. (Amoruso also speaks French and Italian, having lived in different European countries throughout his career.)
As a result, multilingual brains constantly monitor what they hear and say, evaluating the languages they know.
“There is no option to change languages,” Bialystok said.
Therefore, research shows that people who speak multiple languages may have a greater ability to control their attention, focusing on what is relevant and ignoring distracting information.
This control occurs very early in life. Seven-month-old babies growing up in bilingual homes can already tell when languages change. Additionally, they do better on certain attention tests than babies who live in monolingual homes.
The constant challenge of paying attention, distinguishing, and deciding which language to use—and which not to use—seems to train the brain, developing greater resilience.
“A brain that has been exposed to this more complex linguistic environment develops attentional resources or whatever it takes to cope,” Bialystok said. “And so, as life progresses and changes occur in the brain, it becomes more resilient.”
A more efficient brain
In one study, Bialystok and his colleagues used electroencephalograms (EEG) to measure brain electrical activity in bilingual people compared to those who only speak one. They discovered that bilingual people generally had less activity at rest, but more focused.
Other research finds a similar pattern when multilingual people are given simple attention tests: they showed less brain activation compared to monolingual people performing the same tasks, suggesting that knowing more languages made their brains more efficient.
“The electrophysiological activity in the brain of bilingual people is less, it is less affected. It is easier. You don’t have to work as hard to reach the same level. So there is something in this that points to efficiency,” Bialystok said.
Greater brain efficiency—an improvement in its functionality—is important during aging, especially if there are pathological changes that can cause conditions such as Alzheimer’s disease. A more efficient brain could continue to function longer despite the slowdowns of age or illness, he said.
At the same time, knowing another language seems to keep neural networks different and specialized. These networks are made up of different closely connected brain regions that work together in certain functions. With age, “the boundaries between neural networks begin to blur,” Amoruso said.
As he explained, multilingualism could have a mechanism that keeps the brain’s neural network segregated. “It is a way to combat cognitive decline, which is inherent to aging.”
Brains that look younger.
Researchers had evidence that speaking more than one language can make the brain more efficient. But could it also rejuvenate it?
To find out, Amoruso and his colleagues trained machine learning models with images and biological data from more than 86,000 people.
In the study, published last year in Nature Agingit was discovered that, in 27 European countries, those with the greatest number of languages spoken had slower brain aging. A dose-response relationship was observed, meaning that “the more languages spoken, the greater the protection or the more youthful the neurocognitive profile,” Amoruso explained.
On the other hand, speaking a single language was associated with approximately twice the risk of accelerated aging.
However, this research looked at differences between countries, not between people. Therefore, in a subsequent study, Amoruso and his colleagues created brain age clocks using brain electrical activity data from 728 people. The research, recently presented at the Federation of European Neuroscience Societies conference but still awaiting peer review, revealed that people who spoke two or three languages had brains that looked six years younger. Those who spoke four had brains that looked 13 years younger.
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Interestingly, the more similar the languages a person knows, the more brain protection they get, possibly because the brain needs to work harder to distinguish them and switch between them, Amoruso explained.
The relationship between languages and dementia
Knowing more languages appears to increase cognitive reserve, which is the brain’s ability to adapt and compensate despite biological changes related to age or disease.
Research shows that bilingual people receive dementia diagnoses later than people who speak only one language, and that they can function longer even if they have advanced Alzheimer’s pathology.
“For four or five years, they are functional. Their brains look like those of people with Alzheimer’s, but clinically it doesn’t interfere with their functionality,” said Bialystok, who wrote a review in 2021 on how bilingualism contributes to greater cognitive reserve.
How to learn a new language
Learning a new language has many benefits besides cognitive ones, even if you don’t master it.
“It allows you to talk to people you might not have been able to talk to, or travel to places you would have resisted,” Bialystok said. “So it is an experience that opens doors, not closes them.”
Plus, it’s never too late to start. Some research suggests that learning languages in adulthood can improve memory and cognitive flexibility.
The level of cognitive improvement goes hand in hand with the effort dedicated to it. “In my opinion, the longer and more intense the training, the better,” Bialystok said. “The more competent you are, the better.”
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There is no single method to learn a language. You can study more formally in a class or through an app, such as Duolingo or Rosetta Stone. Websites like Italki and Verbling connect you with online tutors. You can complement these lessons by watching series or listening to music in that language, which will help you become familiar with the sounds.
But the key to language is using it, Bialystok said in an email. “I think an approach that includes conversation, especially interaction with a native speaker, is the most effective.”