Does being bilingual make you smarter?

More than half the world’s population uses two or more languages every day
It is hard to estimate the exact number of bilingual people in the world, as there is a lack of reliable statistics. But in 2012, a Eurobarometer survey established that ‘just over half of Europeans (54%)’ are bilingual, and other studies hypothesise that more than half of the world’s population is bilingual.
So what about you? Are you bilingual? Or rather – how bilingual are you?
Being bilingual isn’t black-and-white
To answer that question, first we need to establish what being bilingual means. Contrary to what one might expect, a recent study shows that bilingualism is not a categorical variable (i.e., ‘you are either bilingual or not’), but a multidimensional construct composed of two linked parts. The first of these is language proficiency, and the second is language use.
I, for example, am — or used to be — proficient in German, but I have not used my German regularly for a very long time. Point number one: the more proficient you are in a second language, and the more you use it in your daily life, the more bilingual you will be.
Now that you know the extent to which you are bilingual, the next question is what the advantages and disadvantages of being bilingual are. In this post, I will talk about the cognitive benefits and costs that have been identified by scientific research. It turns out that being bilingual has some costs, but many benefits.
What are the costs of being bilingual?
When I speak in English, my Spanish is also activated. Both languages are active in the brain of a bilingual person when he or she speaks, and this incurs a processing cost, as the brain needs to do two things at once. According to one study, this can mean that ‘the verbal skills of bilinguals in each language are generally weaker than those for monolingual speakers of each language’.
Bilingual people tend to have weaker verbal skills
Bilingual people tend to produce fewer words of any given semantic category than people who only speak one language fluently. In other words, their individual vocabularies in each language tend to be smaller than that of people who only speak one of those languages.
Another study has shown that bilingual people also experience ‘nearly twice as many’ tip-of-the-tongue moments (when you can’t find the exact word you want to describe something) than their monolingual peers. These cognitive costs don’t just affect the lexical level (i.e., vocabulary) but also the syntactic one (i.e., grammar).
What are the benefits of being bilingual?
Don’t worry. There are also benefits to being bilingual, and they far outweigh the costs mentioned above. There are three main cognitive benefits.
1. Bilingualism affects the development and efficiency of the brain’s multifactorial ‘executive control system’.
The bilingual brain is used to handling two languages at the same time. This develops skills for functions such as inhibition (a cognitive mechanism that discards irrelevant stimuli), switching attention, and working memory.
These skills make up the brain’s executive control system, which looks after high-level thought, multi-tasking, and sustained attention. Because bilingual people are used to switching between their two languages, they are also better at switching between tasks, even if these tasks are nothing to do with language.
People who speak two languages have also been shown to have more efficient monitoring systems. A 2009 study showed that monolinguals and bilinguals respond similarly when the brain’s monitoring system is not taxed, but in conditions requiring high monitoring demands, bilinguals were faster. Bilingual people also outperform monolingual people in spatial working memory tasks.
2. Bilingualism has widespread effects on the functional and structural properties of various cortical and subcortical structures in the brain.
Our brains change and adapt as a result of experience. Studies have shown that people who are multilingual have higher density of grey matter, and that older people who are bilingual tend to have better-maintained white matter in their brains.
So, does this make you smarter if you are bilingual? I’m afraid not. I don’t know any study that shows a link between bilingualism and such concepts as executive intelligence, emotional intelligence or intelligence quotient.
3. Bilingualism promotes cognitive reserve in elderly people
Taking part in stimulating physical or mental activity can help maintain cognitive function, and delay the onset of symptoms in people suffering from dementia. The onset of dementia symptoms is significantly delayed – by as much as five years – in patients who are bilingual. The brains of bilingual patients with Alzheimer’s disease function cognitively at the same level of monolingual patients who have suffered less brain degeneration.
What are the limitations to research into bilingualism?
There are some limitations to the research presented above. For example, the bilingual advantage is not always found in young bilingual adults. Some people argue that this is due to the fact that young adults are at the peak of their cognitive development, so the positive effects of bilingualism aren’t as noticeable. Scientists also agree there’s not enough research yet into how and why the bilingual experience affects the brain’s processes in the way it does.
But we can certainly dispel some myths about being bilingual – such as the outdated and disproven idea that growing up bilingual confuses and hinders cognitive development.
On the contrary, being bilingual is a beneficial condition that one is never too old nor too proficient to experience and develop.

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