Does Growing Up Bilingual Confuse Kids or Delay Their Reading?
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Hindi at home, English at school, Tamil with grandparents on the phone — and somewhere in the mix, a relative wonders aloud if all that switching is why your child mixes up words or seems a little behind on talking compared to a cousin who hears only one language. It's one of the most common worries in multilingual Indian households, and it's worth looking at directly.
The core finding
A large 2025 study led by Karolina Muszyńska and colleagues across several European universities tracked 302 bilingual children and 302 carefully matched monolingual children from infancy, using an app through which parents logged milestones as they happened (Muszyńska et al., 2025, Journal of Child Language). Across babbling, first words, tenth words, and first multi-word sentences, the two groups reached each milestone at statistically the same ages. Growing up with two languages did not predict a slower start.
The bigger picture
Psychologist Ellen Bialystok's decades of research, summarised in her book Bilingualism in Development: Language, Literacy, and Cognition (2001), found that bilingual children often show an edge on certain tasks that involve switching attention or ignoring irrelevant information — a plausible side effect of a brain that's constantly managing two language systems. None of this means bilingual children are ahead in some general sense either; it simply means the switching itself is a skill in progress, not a malfunction.
Where it's genuinely more complicated
There is one honest nuance. When researchers test a bilingual child in only one of their languages, that child sometimes scores lower on vocabulary size than a monolingual peer in that same language — an effect documented by Barbara Zurer Pearson and colleagues back in 1993, and revisited in more recent work by Krista Byers-Heinlein's team (2024, Bilingualism: Language and Cognition). But when you count vocabulary across both languages together, totals come out comparable to monolingual children. A smaller English word count alone doesn't capture what a child knows in Hindi, Tamil, or Bengali at the same time — it's a measurement gap, not a developmental one.
What this means this week
- Tonight, read a book in whichever language feels natural in the moment — there's no research basis for a strict "one language, one book" rule.
- Expect some mixing of languages within a single sentence at this age. That's a normal, temporary feature of bilingual development, not a sign of confusion.
- There's no strong evidence for one "correct" order — English-first or mother-tongue-first. Consistent, rich exposure to both matters more than the sequence.
- If speech seems limited across every language your child hears, not just slower in one, that's a different pattern worth raising with a pediatrician — but it's the overall pattern that matters, not the bilingual environment itself.
Sources
- Muszyńska, K., Krajewski, G., Dynak, A., Garmann, N. G., Romøren, A. S. H., Łuniewska, M., Alcock, K., Katsos, N., Kołak, J., Simonsen, H. G., Hansen, P., Krysztofiak, M., Sobota, K., & Haman, E. (2025). Bilingual children reach early language milestones at the same age as monolingual peers. Journal of Child Language, 53(2), 365–388.
- Bialystok, E. (2001). Bilingualism in Development: Language, Literacy, and Cognition. Cambridge University Press.
- Pearson, B. Z., Fernández, S. C., & Oller, D. K. (1993). Lexical development in bilingual infants and toddlers: Comparison to monolingual norms. Language Learning, 43(1), 93–120.
- Byers-Heinlein, K., Gonzalez-Barrero, A. M., Schott, E., & Killam, H. (2024). Sometimes larger, sometimes smaller: Measuring vocabulary in monolingual and bilingual infants and toddlers. Bilingualism: Language and Cognition.