Can learning a new language prevent dementia?

My father decided to learn French at the age of 57. He hired a tutor to meet with him twice a week and diligently completed his homework before each lesson. Before long, he was visiting the French bakery across town to practice his pronunciation (and buy macarons). Now, twenty years later, he is on his third tutor.

At first glance, his retirement hobby seems a bit random – our family has no ties to French-speaking countries – but his motivation went deeper than a passion for pastries. My grandmother developed signs of Alzheimer's in the early 1970s studies suggest that being bilingual can delay the onset of the condition by up to five years.

Attracted by that potential advantage, many people, like my father, have tried to learn a new language in adulthood. According to a survey conducted by language learning app Memrise, 57 percent of users cited “improving brain health” as their motivation for using the program.

But is that really possible? The studies on bilingualism and dementia were conducted in people who have used multiple languages ​​in their daily lives at least since early adulthood. Whether casually learning another language will yield the same cognitive benefits later on is a question for discussion.

How bilingualism benefits the aging brain

Many activities are linked to better brain health in old age, such as getting more education when you're younger, physical activity and cognitively stimulating hobbies. Experts say that speaking multiple languages ​​regularly is possible especially beneficialalthough.

“We use language in all aspects of daily life, so a bilingual brain is constantly at work,” says Mark Antoniou, an associate professor at Western Sydney University in Australia who specializes in bilingualism. “You don't really get that from other enriching experiences, such as playing a musical instrument.”

The age at which you learn another language appears to be less important than how often you speak the language, says Caitlin Ware, a research engineer at Broca Hospital in Paris who studies bilingualism and brain health. “The cognitive advantage is that you have to suppress your native language,” she said, which your brain must do when you try to remember the correct words in another language. “So if the second language is used a lot, you get that cognitive training.”

That process – called cognitive inhibition – is linked to better executive functioning. By improving these types of processes, the brain theoretically becomes more resilient to the limitations caused by diseases like dementia – a concept known as cognitive reserve. The stronger your mental abilities, the thinking goes, the longer you can function normally, even as your brain health deteriorates.

In a landmark document from 2007Toronto researchers found that among people with dementia, those who were bilingual developed symptoms an average of four years later than those who were not. Several studies published since then have reported on this comparable findingsalthough other research found no such difference.

Learning later in life

The evidence for the benefits of learning a second language as a hobby in your 60s is weaker.

Research by Dr. Antoniou and colleagues found that while Chinese adults aged 60 and over improved cognition tests after a six-month language learning program, so did people who played games like Sudoku and crossword puzzles. Another small study found that older Italians who took four months of English classes saw no difference in their cognition scores, but people who didn't take the classes saw their scores drop. Two more recently studies about the subjectpublished in 2023, found virtually no difference in cognitive performance after people participated in language learning programs.

The scientists who conducted these studies offered a number of possible explanations for their disappointing results. One is that the participants were highly motivated volunteers, who may already be at peak performance for their age, making it difficult to see improvements.

“When we recruit participants, we have to be careful: are they really representative of the population?” said dr. Ware, who helped run one of the experiments. “And is their cognitive level perhaps a little too high?”

Another is that the language interventions may have been too short. The handful of studies on this issue have used language lessons that were “very different in length and frequency,” says Judith Grossman, who investigated the subject as part of her PhD at the University of Heidelberg in Germany. In some studies, participants received eight months of lessons, in others only one very intensive week.

For Dr. Antoniou, the limited findings are not entirely surprising. No one would say that learning a new language for six months would be “like having used two languages ​​all your life,” he said. But he does think language classes can provide cognitive benefits because they are intellectually stimulating.

Perhaps more importantly, Ms. Grossman said, learning another language offers other potential benefits, such as traveling or connecting with new communities. For example, my father remained pen pals with his first teacher after she moved back to Paris, and he has traveled to France (and the French-speaking parts of Canada) numerous times.

And at 76, he's as sharp as ever.