Learning another language is a highly complex mental activity. It requires people to remember words, distinguish unfamiliar sounds, recognize patterns, work out grammatical rules and retrieve the right expression at the right moment. All of this happens while listening, interpreting and preparing a response.

Could all this mental activity also help keep an aging brain healthier? Research suggests it can.

Concerns about memory and dementia can send aging adults looking for ways to exercise their brain and maintain cognitive function, whether it is solving crossword puzzles or playing a musical instrument. Language learning might not seem like the same kind of brain exercise, but it is a complex activity that engages several mental processes at once.

I am a linguist who studies language acquisition, use and loss. My new book, “Beyond Words: How We Learn, Use, and Lose Language,” examines language and the mind across people’s lifespans.

Research increasingly suggests that language learning and bilingualism can offer cognitive benefits – including for older adults. Learning another language can also create opportunities for communication and social connection.

A workout for the brain

A person’s brain remains capable of change throughout their life. This ability to adapt in response to experience is known as neuroplasticity.

Learning unfamiliar sounds, vocabulary and grammatical patterns requires the brain to form and strengthen connections. Language learning engages several mental processes at once, requiring people to absorb and retrieve information, notice when something does not work out, and adjust. This sustained mental effort makes language learning a particularly rich form of cognitive exercise.

Research on bilingualism has found differences in both the brain’s gray matter, which contains neurons and their connections, and white matter, which consists largely of nerve fibers linking different parts of the brain.

Studies have shown greater gray matter density or stronger white matter integrity in bilingual people, compared with people who speak one language. These findings suggest that language experience can be reflected in the brain’s structure, as well as its activity.

But brain differences are only part of the picture.

The brain as it ages

One reason researchers are interested in language and aging is the idea of cognitive reserve. This term refers to the ability to maintain cognitive function despite age-related changes or damage to the brain.

Bilingualism has been proposed as one factor that can help the brain cope with the effects of aging, because managing two languages places ongoing demands on people’s attention and cognitive control – ultimately helping to strengthen cognitive reserve.

Some studies have found that bilingual people who develop dementia show symptoms at a later age than people who speak one language. This suggests that bilingualism may provide some protection against the effects of brain aging, although it does not necessarily prevent dementia or the brain changes associated with it.

The potential benefit may therefore be greater resilience in the face of those changes, rather than prevention of the underlying disease.

Learning later in life

This raises another question: If lifelong bilingualism may help protect the brain as we age, can people gain similar benefits by learning a language later in life?

Age changes the way languages are learned, but adults remain capable of learning new languages throughout life. Adults and kids bring different strengths to the task. Children tend to have advantages with pronunciation and some aspects of grammar, while adults bring larger vocabularies and better-developed strategies for learning.

Research involving older adults suggests that learning a language can produce cognitive benefits, although the findings are mixed. The potential benefit may come less from achieving fluency than from the process of learning itself. Language learning is a sustained challenge that keeps people learning, practicing and adapting.

There are social benefits, too. Learning another language can deepen cultural understanding, improve interpersonal communication and encourage people to empathize with other people’s perspectives and experiences. It can also connect people with others from different linguistic and cultural backgrounds, creating opportunities for conversation and friendship.

There is no established formula for how much language learning is needed to provide these benefits. Studies have used everything from intensive classroom instruction to short daily sessions with language-learning apps, over periods ranging from weeks to months, to see whether language learning can improve cognitive function. Rather than a magic number of hours, what matters may be sustained engagement in a challenging activity like learning a new language.

Building cognitive resilience

Learning another language is not a miracle cure for aging, and it cannot guarantee protection against Alzheimer’s disease or other forms of dementia.

But it is an unusually rich form of mental activity.

Perhaps the most useful way to think about language learning is not as a way to keep the brain young, but as a way to support cognitive resilience – the ability to keep learning, adapting and functioning despite the changes that come with age.

Aging inevitably changes the brain, but people retain the capacity to learn throughout life. Keeping our brains engaged in demanding new activities may contribute to that resilience.