We’ve all heard learning a second (or third) language is good for you. And research has shown bilingual brains are different to the brains of people who speak only a single language. But what exactly are the advantages of being bilingual?
Out of the mouths of babes
Less than a century ago, most people believed bringing up a child speaking two languages was a bad idea. Almost all kids who are brought up bilingual put words from both languages into the one sentence at some stage. This mixing is often argued to be a sign that learning two languages at once is too confusing and will result in a child who speaks both languages badly. But children definitely don’t mix languages together because they can’t tell them apart.
We now know young babies are able to learn any language they are exposed to and newborns can already clearly distinguish between the sounds of different languages. Together, the world’s languages contain about 800 elements: 600 consonants and 200 vowels. And babies can tell them apart no problem. In fact, babies start to become familiar with language while still in the womb. But between the ages of about 8 and 12 months, babies become attuned only to the sounds of the languages that have been spoken to them.
Each language uses a set of only about 40 elements and by 12 months, babies are only good at distinguishing between the elements of their own language. What does it matter if a baby can distinguish between the sounds of different languages? Because it’s the start of learning to speak a language and science suggests there are plenty of advantages to being bilingual.
The bilingual advantage
Put together, research over the last fifty years has resulted in a widely-accepted theory called the bilingual advantage. Much of this research has focused on what’s called executive function. Executive function is basically your brain’s CEO. It’s the set of mental skills you use to get stuff done: plan, focus your attention, solve problems, remember instructions and switch between different tasks.
There is plenty of research showing bilingual brains are better at executive function. And this advantage can already be detected in 11-month old babies. We know that in a bilingual’s brain, both languages are active, even when only one language is being spoken. This is because someone who is bilingual has to constantly work out which language is relevant to the situation at hand. Dealing with this constant internal conflict, and choosing to focus on one language at the expense of the other, builds a brain that is better at paying attention to things, and switching between tasks. It makes sense this constant battle between the languages has a noticeable effect on the brain: the process has been likened to brain bodybuilding.
How strong is the evidence?
But in recent years a number of researchers have started to argue with the idea of the bilingual advantage. Not that there aren’t social or personal benefits to being bilingual (of course there are many), but that the evidence for heightened brain function is flimsy. Part of the problem may be what we call publication bias: in this case, when research finding advantages of bilingualism is more likely to be published than research that doesn’t find any advantage. While some studies have found evidence for advanced executive function, it doesn’t seem to be as established a theory as it is often reported. Regardless, there’s no question being bilingual has an effect on your brain: bilingual brains are different in structure to monolingual brains. For example, bilingual brains have more grey matter in brain areas connected with language learning and processing.
There’s more to being bilingual than just improved executive function anyway. There are many studies that show speaking two or more languages delays the onset of dementia. On average, bilingual sufferers of dementia started showing symptoms five years later, and were diagnosed four years later, than dementia sufferers who only speak one language.
Bilingual adults are better at recalling events from their lives than those who are monolingual. This sort of memory, called episodic memory, is known to commonly decline as we age. Research has also shown people who are bilingual are twice as likely to recover normal brain function after stroke than people who only speak one language. And bilinguals are more creative thinkers than monolinguals.
Sounds pretty good, doesn’t it. The only problem is, there’s a critical age you need to be under if you want to become truly bilingual. Many studies have suggested puberty is the critical age, but other research has suggested it could be as young as five. Either way, for many of us, that ship has well and truly sailed. On the upside, just five months of living overseas and speaking a different language resulted in positive changes to the brains of young adults. Might be time for an extended overseas holiday and some language immersion.