Raising a Bilingual Child

The short version

• Bilingual children reach the big milestones on the same timetable as children learning one language. Babbling around the same age. First words around one year. Little two-word phrases around two.
• Count words across both languages. A toddler who says "dog" and "chien" knows two words. Counted that way, bilingual toddlers know as many words as their peers with one language, sometimes more.
• Mixing two languages in one sentence is a normal part of learning, not confusion. Most children separate their languages well before school.
• Hearing two languages does not cause delay. The professional bodies for speech and language in the US, the UK, Germany, Australia and Canada all say the same thing, plainly.

What we will not promise

You may have read that bilingualism makes children "smarter". We would love that to be true, and we sell bilingual books. But the largest analysis to date, covering more than 23,000 children, found no general thinking advantage once publication bias was accounted for. So we will not claim one.

Here is what the research does keep showing. A child's words grow where the language minutes are: the more of a language a child hears, up close and warm, the more of it they learn. And there is early evidence that children who grow up around two languages tune in a little sooner to what another person means. Those are quieter promises. They are also the true ones.

Which language should you read in?

• The one you speak best. Pediatric guidance is clear: children learn best from people who feel at home in their language. A rich story in your own language beats careful reading in one you find harder.
• Your home language is an investment, not a detour. Skills built in the language of your family support the language of school later. Reading in your language never costs your child the other one.
• Grandparents count. A grandmother or a grandfather reading in their own language gives your child a rich bath of words and a place in the family story.
• Both kinds of books help. Early research suggests a book with both languages on the page makes it easier to use both in one sitting, and a book fully in your home language is the strongest nudge to read in that language. They work together. That is why our books come both ways.

Small habits that help

• Protect a little daily reading time for the smaller language. The language of the street tends to take care of itself; the language of home is the one that needs the minutes.
• Read the same book again. And again. Repetition is not a rut: it is how toddlers keep new words.
• Ask one little question per page, then wait. Language grows in the back and forth. Every Tella Terra page is built around one question.
• Keep a pattern you can hold. One person one language, one language at home, one language at bath time: any steady pattern your family can keep works. No single method is required.
• Do not aim for perfect. Speak the languages you are comfortable in, often and warmly. That is the whole method.

When to talk to a professional

The signals are the same as for children with one language, counted across both languages together:

• No babbling, or no response to their name, by around 12 months.
• Fewer than 50 words across both languages combined, or no two-word phrases, by 24 months.
• Losing words or skills they used to have, at any age.
• Trouble understanding you in both languages.

A real language difficulty shows up in both languages, not just one. If you are unsure, talk to your pediatrician or a speech-language therapist, and ask for an assessment that covers both languages. One more thing worth knowing: no professional body advises dropping a language, even when a child needs support. If someone tells you to, ask for a second opinion.

The research

• Muszynska, K. et al. (2025). Bilingual children reach early language milestones at the same age as monolingual peers. Journal of Child Language. 302 bilingual children matched to 302 monolinguals; strong evidence for "same timetable".
• Pearson, B., Fernández, S. & Oller, D. K. (1993). Lexical development in bilingual infants and toddlers. Language Learning. The landmark study behind "count both languages".
• Core, C., Hoff, E., Rumiche, R. & Señor, M. (2013). Total and conceptual vocabulary in Spanish-English bilinguals. Journal of Speech, Language, and Hearing Research. Combined vocabulary grows like monolingual vocabulary from 22 to 30 months.
• Hoff, E. et al. (2012). Dual language exposure and early bilingual development. Journal of Child Language. Each language grows with its share of what the child hears.
• Byers-Heinlein, K. et al. (2023). Sometimes larger, sometimes smaller. First Language. 743 children; whether bilinguals look "ahead" or "behind" depends entirely on how you count.
• De Houwer, A. (2007). Parental language input patterns and children's bilingual use. Applied Psycholinguistics. 1,899 families; no single family method is necessary or sufficient.
• González-Barrero, A. et al. (2021). Effects of language dominance on home reading practices of bilingual families. International Journal of Bilingualism. Families drift toward reading in the stronger language; protecting the smaller one is the practical lever.
• Reinoso, L. et al. (2025). ¡Leamos juntos! Journal of Child Language. With a bilingual book, parents used more of their home language, with no drop in English.
• Quirk, E., Brouillard, M. & Byers-Heinlein, K. (2024). Reading in two languages. Bilingual Research Journal. A book fully in the home language is the strongest nudge to read in it; the two formats complement each other.
• Kremin, L. et al. (2022). Code-switching in parents' everyday speech to bilingual infants. Journal of Child Language. Everyday mixing is purposeful and has not been shown to harm learning.
• Lowe, C., Cho, I., Goldsmith, S. & Morton, J. B. (2021). The bilingual advantage in children's executive functioning is not related to language status. Psychological Science. 23,414 children; no general advantage once publication bias is corrected. The reason we make no "smarter" claims.
• Fan, S., Liberman, Z., Keysar, B. & Kinzler, K. (2015). The exposure advantage. Psychological Science. Early evidence that growing up around two languages helps children read a speaker's intent; small samples, so we say "evidence", not "proof".
• Tsybina, I. & Eriks-Brophy, A. (2010). Bilingual dialogic book-reading intervention. Journal of Communication Disorders. Question-and-wait reading works delivered in two languages.
• Grøver, V. et al. (2020). Shared book reading in preschool supports bilingual children's second-language learning. Child Development. A randomized trial with 464 children.
• Hambly, C. & Fombonne, E. (2012). The impact of bilingual environments on language development in children with autism spectrum disorders. Journal of Autism and Developmental Disorders. No added delays from a bilingual home.
• American Academy of Pediatrics (2024). Literacy promotion policy statement. Pediatrics. Read and tell stories in the language you know best.
• ASHA. Learning more than one language. The US speech-language association's plain-language guidance for families.
• Byers-Heinlein, K. & Lew-Williams, C. (2013). Bilingualism in the early years: what the science says. LEARNing Landscapes. A readable myth-versus-fact tour by two researchers.