Jonge kinderen in klaslokaal
Jonge kinderen in klaslokaal

Bilingual child cannot ‘turn off’ their language knowledge

Worldwide, there are more children who grow up learning multiple languages than children learning only one. And yet monolingualism is often taken as a starting point, for example in school. Research by linguist Elly Koutamanis shows that the two languages of a bilingual child are always active in their brain. “A child can benefit from this bilingual knowledge at school.” Koutamanis will receive her PhD on language interaction in bilingual children on 22 March.

When bilingual children use one language, it may be affected by their knowledge of the other. For example, a Greek-Dutch child might think of a barn when hearing the word ‘apotheek’ (‘pharmacy’ in Dutch). That is because the Greek word ‘αποθήκη’ (pronounced apothiki) means ‘barn’. A French-Dutch child might say “Waarom jij huilt?” instead of “Waarom huil jij?” because that is a good sentence in French (“Pourquoi tu pleures?”).

“These kinds of examples do not mean that bilingual children are confused or that they have a language deficiency,” says linguist Elly Koutamanis. “It just shows something about how a language is processed. In order to use a word, we store information about aspects like the word form and meaning. This information is activated in your mind when you listen or talk. In bilingual children, information from both languages is activated. As a result, the two languages can get in each other's way, but this can also have a positive effect. A Greek-Dutch child is likely to have less difficulty with a word like ‘xylophone’ than a monolingual Dutch child, because the Greek word ‘ξυλόφωνο’ (pronounced xylofono) means the same thing. That word is then simply activated twice.”


Koutamanis tested how bilingual children stored and processed words from their two languages. Children aged between 3 and 11 who spoke German, English, Spanish, Greek or Turkish in addition to Dutch completed tests to measure the speed and accuracy of their word recognition and production. The results show that the mental dictionary of bilingual children connects and shares the forms and meanings of both languages, which therefore influence each other. For example, children recognised words that were similar in their two languages both in form and in meaning, for example ‘apple’ and ‘Apfel’, faster than other words. The degree of influence between the two languages does depend on several factors, such as which of the two languages a child hears or uses most often, and how similar the two languages are.

Implications for education

The main conclusion of Koutamanis' research is that knowledge of one language can influence knowledge of the other in a variety of situations, regardless of the specific languages. Bilingual children cannot simply ‘switch off’ their other language. “This also has implications for how we raise and teach bilingual children,” says Koutamanis. She herself grew up as the a bilingual child of two Greek parents. In her primary school class in Delft, more than half the children had a parent who spoke another language. “The emphasis was on Dutch. If that did not go well, there was concern that the child would develop a language deficiency. There was no room for the other language. But that doesn't mean the other language wasn't active. It’s a shame not to take advantage of this, especially because previous research has shown that suppressing a language you speak well takes a lot of cognitive effort. And that while a child can actually benefit from bilingual knowledge: bilingual children process words faster and better if they can use their other language. For example with multilingual reading, whereby a child reads a book they already know in their home language in Dutch, or vice versa. They learn words much faster that way.”

Contact information

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Education, Language