“If your child learns two languages at the same time, they will be confused.”
Another concern of parents is that their children will not know that they are speaking two languages and will end up with one jumbled mess in their heads — they will either mix the languages completely or be unable to decide which language to speak with people. Again, even in the earliest stages of language acquisition, there is no hard evidence to suggest this.
Not so dazed and confused.
Blagovesta Maneva and Fred Genesee observed in a study from 2002 that the babbling of a French-English infant differed depending on whether he was interacting with his English-speaking mother or French-speaking father. Older children are also able to use their languages appropriately — even with strangers they just met. This was tested in an experiment by Liane Comeau which was published in the First Language journal in 2010. In the experiment, bilingual children were paired with adults who only spoke one of the languages. When the children’s conversational partners indicated in any way that they didn’t understand, even by using a very general prompt such as “What?”, the 2- and 3-year-old bilingual children immediately switched to the other language.
It’s often mentioned that bilingual children alternate between two or more languages in the context of a single conversation — a practice which is also known as code switching or code mixing. Well, firstly, children code mix pretty rarely: In a study from 1995, Fred Genesee found that French-English bilingual children from Montreal around the age of two mixed the languages within a single utterance less than 3% of the time on average. These results were later confirmed by an independent study by D. Sauve and Fred Genesee in 2000, where code switching occurred less than 4% of the time.
So in at least 96% of cases, code switching doesn’t occur, and even the remaining 4% don’t necessarily have to be considered problematic: While code switching was viewed critically in earlier times, it’s now generally regarded as a normal and natural product of bilingual and multilingual language use. If you work in a multilingual company like Babbel, you see adults code mix on a daily basis without them being regarded as confused, overwhelmed victims of their language education.
Code mixing could even be seen as an indicator that bilingual children are indeed very aware of the grammatical rules in each language, separately. This can be seen in the fact that the children in the aforementioned studies did not violate any grammatical structures of either language when they code mixed. For example, they did not produce sentences such as “I le like,” since it would be ungrammatical in English (but not in their other language, French). This clearly shows that the children were aware of the grammatical rules in both their languages, and that they considered them separately from each other, rather than transferring rules from French into English and vice versa.