July 25, 2021

I, Science

The science magazine of Imperial College

Does talking to children in several different languages confuse them and slow their linguistic development?

My old colleague Juanma always enjoys telling the story of a girl he knows called Anna. Anna had a Spanish mother and an English father. They lived in Almeria, Spain, until their daughter was about five. They they moved to Belgium, and Anna attended an international school where French and Dutch were spoken. For some reason, Anna didn’t adapt well. She got it into her head that all four languages were actually one tongue, and would interchange the words she knew randomly, no matter what language they belonged to. No one could fathom what was she was talking about, and she was either ignored or bullied at school.

Can children’s brains get mixed up when learning multiple languages?

Distressed, her parents took her to visit a psychologist, who eventually got her mind reorganised; with each language put neatly away into its own mental box. After that she managed to learn all four languages perfectly – and she mastered Italian and German too, in later life.

It’s an extreme story, but bilingual parents can worry about these things. Anxious parents are certainly something Krista Byers-Heinlein is used to. She is a psychologist who works with multilingual communities, studying how children begin to learn languages. Often the adults ask for advice. Some insist they should only speak to their babies in one language, to avoid confusing them. Others are unsure of themselves and simply want to know what the best practice is when teaching a child two languages at once.

The number of bilingual parents is growing rapidly in Canada, where Dr Byers-Heinlein works. The proportion of people who spoke at least two languages grew from 14% in 2006 to 18% in 2011. The numbers will probably keep rising because of policies aimed at preserving minority languages. Immigration is also contributing: 76% of Canadian bilinguals speak an immigrant language, like Punjabi or Mandarin, in addition to English.

Dr Byers-Heinlein, of Concordia University, Montreal, thought the parents’ questions were important. At first though, she had no dependable information to give them. No one had tested how bilingual parents switch languages when talking to their children. The first step was to get that data.

She handed out questionnaires asking if, and when, bilingual parents would switch languages mid-sentence when speaking to their children. Most of the 183 parents’ answers, reported recently in the journal Bilingualism: Language and Cognition, were not surprising. The adults switched to a second language if they couldn’t pronounce a word; if they weren’t sure of it; or if there was no translation for the term they wanted. On the other hand, many refused to switch languages at all. But Dr Byers-Heinlein had not expected the most common response. The majority of parents, 52%, said they switched languages when teaching their children new words. “I hadn’t included a box for that,” says Dr Byers-Heinlein. “But people wrote it in the white space on the form anyway.”

After checking how parents mixed languages the researcher wanted to see how the practice affected their infants. Next, she asked parents to fill out a form recording their child’s vocabulary. She had recruited families with children of two age groups: one for those aged 18 months and one for 2 years olds. Parents ticked off the words that their children understood, and – in the two year olds’ case – those which they could say.

The data revealed a significant trend. The more often a parent would switch language in a single sentence, the smaller the child’s vocabulary. She took into account factors like exact age and gender. The results still showed a clear correlation.

How babies make their debut with language is poorly understood, but the process begins early. Dr Byers-Heinlein’s previous work has shown that babies can already recognise two different languages in the third trimester of pregnancy. Once born, she thinks they continue to pick up language by watching patterns in facial expression and lip movements. They also recognise the inherent rhythms of language, she reckons. Switching tongues suddenly disrupts the beat. This might explain why children who hear frequent language changes take longer to broaden their vocabulary. Although the psychologist points out that correlation does not necessarily mean cause, the data adds weight to her theory.

Luckily for the young bilinguals-to-be, these challenges don’t last long. Studies have shown that grown up bilingual people are more self-controlled than average. “When they see a plate of cookies, bilinguals are better at controlling themselves,” says Dr Byers-Heinlein. She suggests this is because they must constantly suppress one language in order to speak another.

With the results published Byers-Heinlein is in a better position to advise those Vancouver parents. We can expect children who hear lots of language mixing to expand their vocabulary more slowly. But it’s not something to get hung up over, she says. “The most important thing is to talk to children a lot, in whatever language. So just enjoy interacting with your children as much as possible.”

The names of specific people mentioned in this piece have been changed.

IMAGE CREDIT: TEDxPioneerValley2012, flickr.