Worried about raising your child bilingual? Here’s what the research has to say about it
Prominent bilingualism researcher Ellen Bialystok recently did a review of the research into bilingualism all the way back to 1923, and the general consensus may surprise you. Although early studies claimed children raised with two languages suffered because of it, their own results were often not consistent with this conclusion. The studies indicate that there is generally no effect or even a positive effect on development.

Why did the earlier studies say bilingualism has negative effects?

Many of the early studies tested children’s intelligence using IQ tests, which is problematic because IQ tests are strongly correlated with socioeconomic status (SES). In most of these early studies, the bilingual children were of lower SES than their monolingual classmates, and so would have scored less regardless of their linguistic background. Later studies have shown that when you control for SES there is no difference in intelligence between mono- and bilingual children.

Another important factor is that there was a general societal bias against bilingualism. This attitude stemmed from an intuition that it would require more mental resources to learn two languages, and so must cause delays. This attitude may also have had roots in xenophobia, because many bilingual households were immigrant or minority groups.

What areas of development does bilingualism have a positive effect on?

It is important to note that these effects only emerge if both languages are learned equally well, and mostly arise after the child has developed proficiency in both.

Executive functioning

“Executive functioning” refers to the management of cognitive processes. It includes attention, working memory, monitoring, and reasoning. The majority of the documented benefits of bilingualism relate to executive functioning. Bilingual children have consistently shown themselves to be better at solving problems that require a combination of attention and inhibition. Even at as young as 7 months old, bilingual children are more mentally flexible and react more quickly to new information.

  • The fact that children only show significant benefits after they are already skilled in both languages suggests that it is the exercise of learning two languages that causes advantages in executive functioning, rather than the knowledge itself.

Metalinguistic awareness

Bilingual children have a better understanding of what language actually is: a labeling system for the world accompanied by arbitrary rules about how to combine the parts. This means that they have a better grasp on concepts like reality vs. appearance, abstract ideas, general reasoning, and logic. Because they are better at understanding abstract concepts like the visual representation of sound, bilinguals are generally better at learning to read.

Theory of mind

“Theory of mind” is the ability to attribute mental states to other people. This includes recognizing that other people may not feel what you feel, and that other people may not know everything you know. Bilingual children are better at recognizing others’ emotions based on facial expressions. They also perform better in situations where they must recognize that other people’s knowledge differs from their own.

Interestingly, some studies have also found that bilingual children are more creative than monolinguals.

All of the above skills – problem solving, literacy, attentional control – are targeted during schooling, so it stands to reason that bilingual children may have academic advantages over their peers.

Did the review find any areas of development that may suffer due to a bilingual upbringing?

In young children, bilinguals consistently scored worse on verbal measures (e.g. vocabulary knowledge, structural flexibility) than monolinguals while simultaneously outperforming them on virtually all other cognitive measures. This indicates that there is a cost for the cognitive benefits of bilingualism in the form of linguistic performance. This is hardly surprising when you consider there is twice as much information to learn. The review did not specify an age where bilingual children catch up to monolinguals, and it did not examine whether some children just do not catch up. This may be an area for further investigation.

Does it matter which two languages are learned?

In terms of the general cognitive effects described above, it does not matter what the two languages are as long as the child is proficient in both. Literacy was the only area that had any difference depending on the combination of languages. For example, one study found bilingual children learning languages with similar writing systems had greater literacy advantages over those learning languages with distinctly different writing systems – and both groups had literacy advantages over monolinguals. In another study, French-English and “Chinese”-English (unspecified Chinese language) bilingual children had different understandings of how print refers to language.

Source: Barac, R., & Bialystok, E. (2011). Research timeline: Cognitive development of bilingual children. Language Teaching, 44, 1, 36-54.

Katherine Christ, honours Linguistics, Head of Research at Simone Friedman Speech-Language Services