What are the Effects of Bilingualism?

Studies in the first half of the last century appeared to show that bilingual children had lower IQs and that they were outperformed by monolingual children in both verbal and nonverbal intelligence tests. Most of those studies concluded that bilingualism had a negative effect on the child’s linguistic, cognitive and educational development.

Midway through the last century, the opinions changed rather suddenly and researchers found that bilingualism was, after all, a real asset for the child. Many studies came to the conclusion that bilinguals are more sensitive to semantic relations between words, are better able to treat sentence structure analytically, are better at rule-discovery tasks, have greater social sensitivity, and so on.

It would seem that bilingualism enhances problem solving where the solutions depend on selective attention or inhibitory control (abilities of the executive control system, according to Bialystok). This advantage would seem to continue throughout the bilingual’s lifespan and appears to be present in elderly bilinguals.

The advantage shown by bilinguals – as discussed by Ellen Bialystok in a recent interview – is found also in certain metalinguistic abilities, that is, our capacity to analyze different aspects of language (sounds, words, syntax and so on) and, if needed, to talk about these properties. But the advantage appears to be present only when selective attention or inhibitory control are needed to do the task. When the metalinguistic task requires the analysis of representational structures, then monolinguals and bilinguals obtain similar results. This occurs when the task is to explain grammatical errors in a sentence, substitute one sound for another, interchange sounds, etc.

One domain where it would appear that bilinguals do less well than monolinguals is in vocabulary tests such as choosing a picture that illustrates the word spoken by the experimenter. This is not surprising, however, as bilingual children start being affected by the complementarity principle which states that bilinguals usually acquire and use their languages for different purposes, in different domains of life, and with different people. When bilingual children are evaluated in terms of both their languages, then the results improve greatly.

In sum, we now have a fuller and more complex picture of what the differences are between monolinguals and bilinguals – when differences exist!