What the research says about why children mix languages
One of the most commonly asked questions about raising bilingual kids is whether language mixing is something to worry about. In most cases of mixing, kids will keep the grammar structure of one language and add nouns of verbs from the other. For instance, mixing Spanish into English could sound like: “I don’t want to dormir”. If your child does this a lot, you might start to wonder if this is a sign they are confused, and if learning multiple languages is too much for them. Rest assured: this isn’t the case.
The old worry: mixing as deficit
For much of the 20th century, switching between languages was read as problematic: a child who couldn’t keep the two systems straight, or whose vocabulary in each language was too thin to make it across a full sentence. Echoes of this view persist in some newer work too. Yow and colleagues [1], for instance, studied Mandarin-English bilinguals aged five to six and found that more code-switching was associated with weaker language skills.
So the worry isn’t pulled from nowhere. If kids are less proficient in a language, they may mix more into that language to cover up any gaps while speaking. But it would be too quick to conclude that mixing means a child is failing to learn a language or, even worse, has some delay or language disorder. Instead, research that looks at why children mix shows that it is a normal part of bi/multilingualism, and that the amount of mixing is often a reflection of their environment.
The newer picture: mixing as mirroring
Recent studies have shown that children’s language mixing tracks the mixing in their family or wider context. Kids are mirroring what they hear.
Lanza’s research [2] showed that the way parents respond to their child mixing (whether they pretend not to understand a switched-in word, repeat back in the ‘target’ language, or move fluidly between languages) shapes how much their children mix. Comeau and colleagues [3] also reported that children’s language mixing was directly related to the mixing in their input. These studies show that children mirror the people they talk to in their mixing behavior.
Yip and Matthews [4] pushed this further. Looking at Cantonese-English bilingual children, they found that mixing patterns were driven by input characteristics rather than by which language a child was dominant in. The children in their study mixed English into Cantonese far more than the reverse, even when Cantonese was their stronger language.
Patuto and colleagues [5] also found that children’s setting affected how much they mixed languages: monolingual contexts produced less mixing, bilingual contexts produced more. Children adjusted to who they were talking to.
So is language mixing a reason to worry?
To recap, if your child mixes languages, this is no evidence that they’re confused, struggling, or failing to learn a language; what it can indicate is that one language is more advanced or active than the other. This is, too, a very normal part of bilingualism or multilingualism. Languages are usually not known equally.
Besides language dominance, the amount of mixing is often tied to how much mixing children hear around them. This is one of the most robust findings in this corner of the literature. If you switch between, say, English and Spanish in every sentence at home, your child will too. If you keep your own speech relatively separated in a given context, your child will follow you there.
My Languages, My World
A workbook for bilingual and multilingual children to explore their own language landscape. They reflect on when, where, and with whom they speak each language, and set their own language wish for keeping their languages close.
References
[1] Yow, W. Q., Tan, J. S. H., & Flynn, S. (2018). Code-switching as a marker of linguistic competence in bilingual children. Bilingualism: Language and Cognition, 21(5), 1075-1090. https://doi.org/10.1017/S1366728917000335
[2] Lanza, E. (1997). Language Mixing in Infant Bilingualism: A Sociolinguistic Perspective. Oxford: Oxford University Press.
[3] Comeau, L., Genesee, F., & Lapaquette, L. (2003). The Modeling Hypothesis and child bilingual codemixing. International Journal of Bilingualism, 7(2), 113-126, https://doi.org/10.1177/13670069030070020101
[4] Yip, V., & Matthews, S. (2016). Code-mixing and mixed verbs in Cantonese-English bilingual children: Input and innovation. Languages, 1(1), 1-14. https://doi.org/10.3390/languages1010004
[5] Patuto, M., Hager, M., Gil, L. A., Eichler, N., Jansen, V., Schmeißer, A., & Müller, N. (2014). Child-external and -internal factors in bilingual code-switching: Spanish, Italian, French and German. In A. Koll-Stobbe & S. Knospe, eds., Language Contact around the Globe. Proceedings of the LCTG3 Conference. Bern: Peter Lang, pp. 191-209.