Skip to main content

Verified by Psychology Today

10 Questions on Bilingualism

François Grosjean weighs in on the ability to speak multiple languages.

When a recent study revealed that early exposure to multiple languages promotes the development of effective communication skills, it added to the established list of bilingualism benefits (e.g., enhanced executive control, working memory development, delayed onset of cognitive decline). Besides various cognitive and social perks, the knowledge of foreign languages can bring along a few noteworthy opportunities. At the start of our language learning journeys, for instance, there is the thrill of hearing the new words in our own voices; the rush of sailing through streams of sentences that only a few months ago were impermeable. Then, there is the possibility of discovering a shortcut to the heart of the cultures we are exploring. Sometimes, it’s the mere convenience of finding just the right word to express a feeling (or order a beer). And then other times, it’s the invitation to look at the world (and at ourselves) in a new light.

According to some estimates, more than half of the world’s population is bilingual. Yet, fascinations with the ability to speak multiple languages persist, among researchers and language learners alike. Here are 10 questions answered by bilingualism expert François Grosjean, the author of Psychology Today’s “Life as a Bilingual” blog and the book Bilingual: Life and Reality.

1) When are you considered a bilingual?

Bilinguals are those who use two or more languages (or dialects) in their everyday lives. For too long, bilinguals were erroneously seen as those who are equally, and fully, fluent in their languages. This is very rarely the case, and this more realistic definition of bilingualism has allowed many people who live with two or more languages to accept who they are—bilingual, quite simply (see here).

2) Are there differences in the brains of bilinguals and monolinguals?

In a recent interview on my blog, a leading researcher in the field, Dr. Ping Li of Pennsylvania State University, argues convincingly that there is no "monolingual cortex" or "bilingual cortex," but rather that the brain uses the same neural structures and resources to handle the bilingual's languages, but in different ways (see here).

3) Can adults learn to speak a foreign language without an accent?

Researchers do not agree on an age limit distinguishing between not having an accent in a second language and having one, but it is usually given at around 10 or 12, even 15 years old. There are reports of highly motivated people, such as language teachers, who have learned a language later on in life but compensated for that disadvantage with intensive contact with native speakers, extended stays in the country in question, the study of phonetics and pronunciation and so on, and hence who can "pass" as native speakers of the language.

4) Is it possible to be equally proficient in L1 and L2?

Most bilinguals use their languages for different purposes, in different situations, with different people­. Hence, they simply do not need to be equally competent in all their languages. The level of fluency they attain in a language (more specifically, in a language skill) will depend on their need for that language and will be domain specific. I have called this the Complementarity Principle (see here). It is extremely rare that bilinguals have equal proficiency in their languages.

5) Should parents be wary of their bilingual children mixing languages (i.e. Should L1-L2 code-switching within sentences be prevented)?

The intermingling of languages in children is normal, especially if the parents are themselves bilingual and intermingle their languages too. Code-switching and borrowing in children is not a factor in how well they will acquire and maintain two or more languages. Much more important issues are when the languages are acquired, which bilingual strategy the parents use, whether children have a real need for each language, what type and amount of input is used for each language, and what other linguistic support parents can count on (see here).

6) Do bilinguals dream in different languages?

In a small survey I undertook, some 64 percent of bilinguals and trilinguals said that they dreamed in one or the other language, depending on the dream (i.e. when a language was involved, of course). Once again, the Complementarity Principle is at work here: depending on the situation and the person they are dreaming about, they will use the one language, the other, or both (see here).

7) Does speaking different languages affect the way bilinguals feel and think?

Some bilinguals report being different in each of their languages. It has even been proposed that bilinguals change personality when they change language. I have written two posts on this topic (here and here) and basically, what is seen as a change in personality is most probably simply a shift in attitudes and behaviors that correspond to a shift in situation or context, independent of language. This is true of monolinguals also ­– they may well behave differently and sometimes change attitudes and feelings with different people even though the language is the same.

8) When bilinguals talk, do they mentally translate from L1 to L2?

Translating from L1 to L2 is mainly found in the early stages of second language acquisition. When people become bilingual, i.e. use two or more languages in everyday life, they no longer translate or only do so on rare occasions.

9) When children are introduced to two languages simultaneously, how does it affect their development? (i.e. Does it delay their speech? Do they end up with a smaller vocabulary in each language?)

An older myth surrounding bilingualism is that bilingual children are delayed in their language development. There is simply no research evidence to that effect and we now know that their rate of language acquisition is the same as that of their monolingual counterparts (see here for other myths). As for lexical knowledge in bilingual children, I discuss this complex issue in a post which shows that children are influenced by the Complementarity Principle, as are adults (see here).

10) What do you think is the biggest advantage of bilingualism?

Instead of giving just one, allow me to list a few put forward by bilinguals themselves: they can communicate with different people, of different cultures, in different countries; they have the impression that knowing several languages helps them acquire other languages; bilingualism fosters open-mindedness, offers different perspectives on life, and reduces cultural ignorance; it also gives you more job opportunities and greater social mobility. For a discussion of these advantages and others, see here.

Many thanks to François Grosjean for being generous with his time and insights.


Bialystok, E., Craik, F. I., & Luk, G. (2012). Bilingualism: consequences for mind and brain. Trends in Cognitive Sciences, 16(4), 240-250.

Carlson, S. M., & Meltzoff, A. N. (2008). Bilingual experience and executive functioning in young children. Developmental Science, 11(2), 282-298.

Fan, S. P., Liberman, Z., Keysar, B., & Kinzler, K. D. (2015). The Exposure Advantage: Early Exposure to a Multilingual Environment Promotes Effective Communication. Psychological Science, 26(7), 1090-1097.

Morales, J., Calvo, A., & Bialystok, E. (2013). Working memory development in monolingual and bilingual children. Journal of Experimental Child Psychology, 114(2), 187-202.