The characters in Sanaz Toosi’s English speak two languages, and they’re not alone. There are over 6,000 languages spoken across the world, and for thousands of years knowing at least two of them has been both a necessity and a means of survival for people due to migration, trade, and conquest. Citizens of the Ottoman Empire in the 18th century spoke Arabic, Farsi, and Turkish each day. Today migrants, immigrants, refugees, and asylum-seekers often assimilate by learning the dominant languages of the countries where they resettle. It’s a fact: bilingualism is the historical norm. It’s everywhere. Except for the United States: recent U.S. census data shows that around 20% of Americans speak a second language, compared to approximately half of the world’s population. So, are monolingual Americans missing out? As it turns out, the answer is yes.

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THE BILINGUAL BRAIN

Research shows that there are distinct cognitive benefits to being bilingual. For a long time, experts believed that bilingualism was harmful to language proficiency and verbal intelligence, particularly for children. The underlying assumption was that navigating two languages was confusing. This changed in 1962, when researchers in Canada found that 10-year-old bilingual French/English speakers outperformed monolingual English speakers on both verbal and non-verbal tests. Since then, an overwhelming number of studies have been conducted that support the theory that bilingual people have cognitive advantages over monolinguals. Dubbed “the bilingual advantage,” it’s been found at every stage of life, from newborn children, where being bilingual helps infants perceive and process language, to the elderly, where being bilingual helps to delay the onset of dementia by three to four years.

So what is this cognitive advantage that bilingual people possess? Imagine that you’re three years old, sitting at a desk, and in front of you are two boxes and a stack of cards. One box has a blue elephant on the front and the other has a red star. You’re told to sort the cards in the boxes by shape (elephants go in one box, and stars in the other), no matter the color. Here’s the tricky part: after sorting for a while, you’re told that the rules have changed. Now, you’re supposed to sort the cards in the boxes by color, no matter the shape. This test is called the Dimensional Change Card Sort, and if you’re bilingual, you’re much more likely to have an easier time with it because of your ability to follow the new rule while suppressing any impulse to go by the old rule. That’s because bilingual people have a cognitive advantage: a higher degree of executive function.

Executive function is a series of interconnected mental skills called inhibition, interference control, working memory, and cognitive flexibility. These skills allow us to concentrate, have self-control, follow instructions, and multitask, among other things. It’s sort of like an executive at a business, except the business is your brain, and instead of managing employees, it manages your attention. We use executive function in almost every facet of our lives, and it can have a positive impact on our relationships, our job performance, and our mental health. Unfortunately, we aren’t born with executive function. It has to be learned and developed over time. Bilingualism is the ultimate executive function training tool.

Research has shown that taking part in complex, high-concentration tasks like juggling or playing video games can help develop the parts of the brain associated with executive function, as well as long-term, sustained tasks like musical training. Being bilingual is both a complex and long-term task, cognitively speaking. Bilingual people are constantly monitoring the situation they’re in to select the correct language to use, which is complex. And because they do it throughout their lives, it’s long-term.

If you don’t speak a second language, don’t despair. There’s still time for you and your brain: learning another language at any point in life, even if you don’t become fluent, carries many of the same benefits.

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THE BILINGUAL HEART

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