Is my child mixing languages?

A young child who puts Spanish and English in one sentence is not confused. King & Mackey call this code-mixing a short-term phase for children learning two languages, and "perfectly normal and quite common." It is a different thing from code-switching, which fluent bilinguals do on purpose.

What is going on

Two different behaviors get the same label, "mixing." King & Mackey separate them, and the difference tells you what you are hearing.

• Code-mixing is a young child combining words or structures from both languages in one sentence. The reason, in their account: the child's two language systems, and the social rules for which language goes with which person, are still being sorted out. It is short-lived, and it is not a sign of confusion.
• Code-switching is a fluent bilingual, an adult or an older child, deliberately alternating between languages and following complex, systematic rules. King & Mackey write that being able to code-switch successfully "means the speaker has a detailed grammatical understanding of both languages." It is a sign of mastery, not a lack of it.

So the mixed sentence at your table is the first kind. Her two languages are not tangled beyond repair. She is still working out which one belongs where. That is why the phase is described as short-lived: as the sorting gets done, the mixing is expected to fade. A fluent adult who switches mid-sentence is doing something else, and doing it well.

What to do tonight

On King & Mackey's account, the phase does not need correcting. What you do control is how you answer when she uses the other language. Elizabeth Lanza studied two Norwegian-American families, and King & Mackey report that she identified five main strategies parents use, from pretending not to understand to code-switching themselves. This is their account of her study, not the study itself.

1. Pretend not to understand. Ask her to say it again. This is the strategy that pushes hardest toward one language.
2. Make a guess in the language you want. Often a yes/no question, such as "Do you want the ball?" Gentler than the first.
3. Repeat back in the other language. You say what she meant, with no question and no correction.
4. Move on. Continue the conversation in whichever language, without steering.
5. Switch with her. Reply in her language for a sentence or more.

King & Mackey report that children's competency levels were higher when parents used more of the first two, the one-language strategies, and especially when one language is in a weaker position. If you are building the weaker language on purpose, those two are the ones to try. If you are not pushing either way, the last three keep the talk bilingual, but moving on does not build the weaker language the way the first two do. The next article covers all five in detail.

A simple way to use this tonight: first, ask whether you want to push one language right now. If you do, choose a one-language response and use the same one through the evening. If you do not, choose the response that is easiest for you to say without thinking. In neither case do you need to comment on the mixed sentence itself, because on this account there is nothing in it to fix.

What is still unknown

The text we read for this site calls code-mixing a "short-term phase." No source read for this site gives an age by which it stops, or says how long it lasts for one child, and none says when mixing should lead you to ask a professional. We do not offer a number we cannot trace.

Lanza's finding comes from two families, and we have it only through King & Mackey. Whether the way you answer changes the outcome for your own child is not something these sources settle.