Bilingual Toddlers and Language Mixing

The advice families are most often given is wrong

Bilingual families are still routinely told to drop the home language and speak only the community one, usually with the best of intentions and often by someone whose job does not include speech and language development. The professional bodies do not support it.

The American Speech-Language-Hearing Association is explicit that using your languages with your child will not confuse them, will not cause or worsen speech or language problems, and will not slow down their learning. Its advice is the opposite of dropping a language: "start early. Use your languages with your child often and as early as possible."

Milestones do not slip

The headline finding is that the early timeline is the same. ASHA states that most multilingual children, like children learning a single language, start using their first words by 1 year old and two-word phrases such as "my ball" by 2 years old.

The CDC's checklist for 2 years gives the monolingual reference point — most children say at least two words together by then — and, importantly for bilingual families, words from both languages count towards that total. ASHA says so directly: if those first words come from different languages, that is fine.

The CDC also frames its checklists carefully. They describe what most children do at a given age and are not a screening or diagnostic tool; the CDC states its milestone resources are not a substitute for standardised, validated developmental screening tools. They exist to prompt an early conversation rather than to reassure or alarm.

Mixing is a feature, not a fault

Children learning two languages routinely produce sentences that draw on both, sometimes within a single phrase. ASHA calls this expected: "don't worry about mixing languages. Sometimes children might blend words or grammar rules from different languages. It's an expected part of learning and using more than one language at a time."

Adult bilinguals do exactly the same thing, deliberately and skilfully, when talking to other bilinguals. In a toddler it usually reflects the practical fact that they know a word in one language and not the other, and are reaching for the one they have.

It is also worth knowing that the two languages will not develop in step. Vocabulary tends to be distributed across both, so counting words in one language alone will always undercount what a bilingual child actually knows. Which language is stronger can also change — ASHA gives the example of a child who speaks primarily Spanish at home starting to use more English at school.

What determines how well each language develops

Exposure and use, rather than talent or timing. ASHA notes that how a child learns their languages depends on the type and amount of language exposure and the practice they get using each one, and that using more than one language takes practice like any other skill.

That has a practical consequence. A language a child only ever hears, and never has to produce, tends to become a language they understand but do not speak. If you want a child to speak a home language rather than only understand it, they need situations where it is the language that works — grandparents, video calls, songs, books and other children.

ASHA's other two tips are about atmosphere rather than method: be supportive, creating daily chances to use the languages and celebrating the benefits of being multilingual, and value practice over perfection by encouraging your child to talk even when they make mistakes.

The quiet period, and what it is not

A child who has been speaking one language at home and then starts nursery in another often goes noticeably quiet for a while in the new setting. This is a well-recognised pattern of listening before producing, and it is not the same thing as a language disorder. It is also a reason not to assess a bilingual child on the basis of the community language alone in the first months of exposure.

The one thing that does signal a difficulty

This is the single most useful diagnostic principle in the area, and NHS speech and language services state it plainly: a bilingual child with a speech and language disorder will show difficulties in all the languages they speak. A child who is fluent, chatty and age-appropriate in their home language, and quiet in the community language they have only recently met, does not have a language disorder; they have less exposure to one language.

NHS guidance in the same vein notes that if a child's use and understanding of their home language is age appropriate or close to it, and their social communication skills are appropriate, there is no need to refer to speech and language therapy. The RCSLT's clinical information on bilingualism underpins the same approach for therapists, who are expected to assess across all of a child's languages rather than only the dominant one in the setting.

What to raise, and how

The flags are the same as for any child, applied across both languages. Worth mentioning: no words at all by around 18 months, no two-word combinations by around two, speech that nobody outside the family can understand by around three, or a child who does not seem to understand what is said to them in either language.

Losing words or skills already gained is the flag that outranks the others at any age, and is a reason to ask now rather than wait. The HSE makes the general point that you can raise a communication concern at any time rather than waiting for a scheduled review, and the AAP's guidance on language delay in toddlers takes the same line about acting on a concern early.

When you do raise it, say what your child does in each language, with examples, and say how much they hear each one and from whom. A speech and language therapist needs that picture to interpret anything they see, and without it a bilingual child is easy to misjudge in either direction.