Language mixing has no negative effect on toddlers’ vocabulary development, Concordia research shows

Parents in bilingual and multilingual families can wrestle with when and how to expose infants and toddlers to words in different languages. However, a new paper from the Concordia Infant Research Lab shows that language mixing does not harm a child’s ability to learn words.

In fact, switching languages, even mid-sentence or to introduce a single word, is considered both a common and flexible way to communicate in multilingual homes.

“We found that language mixing is often an intentional strategy rather than something parents do subconsciously,” says PhD student Alexandra Paquette, the study’s lead author. “There was no strong evidence that vocabulary size was tied to language mixing. We found that children were able to successfully navigate two languages, even when they appeared in the same sentence. Parents don’t need to worry that mixing harms their child’s ability to learn new words.”

Franglais begins at home

The study, published in the journal Behavioral Sciences, looks at data from almost 400 Montreal children being raised in bilingual homes. The Canadian metropolis benefits from a linguistically diverse population. French and English are both societal languages, meaning large portions of the population speak one or both. The city’s linguistic makeup is also enriched by its significant immigrant population, who speak multiple heritage languages. The most common are Spanish, Arabic and Italian.

The researchers analyzed two groups: French-English bilingual families and families who speak a heritage language along with English and/or French. Parents completed detailed questionnaires about how often they mixed languages, their reasons for doing so and how much of each language their child heard. They also documented their children’s understanding and use of words.

The results show that language mixing is common, but its frequency varies depending on the family’s linguistic background. French-English parents tended to mix less than heritage-language parents, likely because both societal languages are well supported in Montreal. Heritage-language parents mixed more often, especially borrowing English or French terms while speaking their heritage language.

Parents of all backgrounds said they switched languages for several reasons: they could not find the right word in English, French or their heritage language; no good translation was available; or they wanted to introduce a new word to their child. Parents in French-English families with older toddlers were more likely to deliberately mix languages to encourage language development.

The researchers point out that language mixing had almost no effect on a child’s vocabulary score in either French-English or English- or French-heritage language families. Even if parents mixed often, children knew the same number of words.

A unique linguistic environment

Montreal’s particular makeup as a city with two status languages supplemented by many heritage languages shapes how parents raise their bilingual children. Language mixing is a byproduct of a cultural context in which language mixing is common in daily life in both English and French communities.

“This project shows us how flexible children when it comes to language development,” says co-author Krista Byers-Heinlein, a professor in the Department of Psychology.

“Rather than confuse children, language mixing can be a real teaching tool that parents have in their toolbox. Parents are strategic about it, and our research finds that it is either neutral or beneficial when it comes to vocabulary.”

Read the cited paper: “Parental Language Mixing in Montreal: Rates, Predictors, and Relation to Infants’ Vocabulary Size”