Does learning two languages confuse a child?

If you have heard that raising a child with two languages makes them muddled, you are not alone. It is one of the oldest worries in parenting, and it still comes up in playgrounds and on school forms. What does the research say?

Do children get confused by two languages?

The best-known parent-facing review of the field comes from two researchers who study bilingual babies. They found no evidence that bilingual children are confused. Infants can tell their two languages apart from very early, and even four-month-olds can distinguish silent talking faces speaking different languages (Byers-Heinlein and Lew-Williams). They also note that the field is young and many questions remain open, which is a fair caution.

A university speech and language lab makes a similar point for parents: children are good at telling languages apart, and occasional mixing is normal and does not mean something is wrong (UConn Hello Lab).

What about children who mix languages in one sentence?

It looks like confusion, and it is often not. The review describes mixing words from two languages as a normal part of bilingual development. It often reflects what the child hears around them, or a word they do not yet have in one language, and it follows predictable patterns. The UConn page adds that switching between languages may reflect a child making the most of both.

The honest part: the evidence on whether a lot of mixing by parents affects a child's vocabulary is mixed. The review mentions one study that linked heavy parental mixing to smaller vocabularies and others that found no link. The authors say the jury is still out. If you naturally mix at home, there is no strong research case for panic, and no strong case for changing your habits wholesale either.

Will my child have a smaller vocabulary?

Possibly in each language alone. Bilingual children usually know fewer words in each language than monolingual children of the same age. When the words from both languages are counted together, with a word and its translation counted once, the total is roughly comparable (Byers-Heinlein and Lew-Williams). The authors point out that a smaller vocabulary in one language can still affect communication in that language, although the gap may narrow over time.

For parents this means two things. First, do not compare your child's English vocabulary with a monolingual friend's and conclude something is wrong. Second, if you want a particular language to be strong, give it real exposure.

What about speech delay?

On delay, the same review reports no higher risk of language difficulties, delays or disorders for bilingual children than for monolingual ones. It adds a caveat that matters: some bilingual children do have delays, and clinicians need bilingual-informed assessment, because tests designed for monolingual children can wrongly suggest a delay. If you have a concern, the authors suggest talking to a paediatrician and, ideally, a speech pathologist who understands bilingual children.

Why does the myth stick around?

Part of the reason is what parents see. A toddler who answers in the wrong language, or who pauses to find a word, can look muddled, and a child who knows fewer English words than a classmate can look behind. The research points to ordinary explanations: the child is drawing on two languages at once, and may simply lack a word in one of them. Another part is simply that people who hear the worry repeated often assume it must have a basis. The reviews we read say it does not.

What should parents actually do?

The review's advice for parents is practical rather than rigid. In our words:

• Give plenty of interactive exposure to each language. Talking with people counts for more than screens.
• Treat one-person-one-language as an option, not a rule. It is neither necessary nor sufficient. Choose an approach that gives each language a fair share.
• Be honest about how much of each language your child really hears. Not how much you wish they heard.
• Support the minority language. A language that is not used at school is at more risk of fading, so seek out other children and adults who speak it.
• Do not wait until you are fluent. Starting early helps and it is never too late.

If your family speaks a language other than English at home, you are in large company. The 2021 Census recorded Mandarin as the most common language other than English used at home, at 2.7 per cent of the population, followed by Arabic, Vietnamese, Cantonese and Punjabi (ABS). The Australian Curriculum's Chinese entry has a pathway for students who speak Chinese in the home (Australian Curriculum).australiancurriculum.edu.au/teacher-resources/understand-this-learning-area/languages)). Our piece on keeping a heritage language going looks at this in more detail.

What if you are adding a language later, not raising a bilingual baby?

Most of the research above is about children who hear two languages from the start. Learning a second language at school or at home from a later age is a different situation, and the findings do not transfer neatly. Our piece on the best age to start covers what is known there. In both cases, the practical advice is similar: regular, interactive practice.

A calm next step

XLingo is a course for families and adults, and it is not meant to replace talking with real people. If you want to see how it works, there is a 7-day free trial.