Exposure and need
My native language is French. My wife’s native language is Turkish. We have been trying to raise our children (3 and 2 years old) with a bicultural approach. My wife speaks to them in Turkish, I speak to them in French. (Together, we talk in English, but that’s another story.)
I thought this approach would naturally lead to our kids becoming fluent in both French and Turkish. It is not the case. While they do seem to understand both languages equally well, they spontaneously speak in French. Why? Because we live in France. Parents have a massive influence on their children, but a third party comes into play: the other people they meet on a daily basis. In most situations, the environment you expose your children to will turn one language into the majority language (in our case, French), and the other one into the minority language (Turkish).
This first discovery led to a second one. Exposure to a language is not enough to learn how to speak it, you must also have a need to speak it. Thanks to my wife talking to them only in Turkish, they are well exposed to their minority language. But the need to speak Turkish is not there, and the mind is lazy. Indeed, everyone they need to talk to on a daily basis (me, the daycare professionals, their friends, the janitor) understand French. Even my wife understands them when they speak French to her. And unless she remembers not to respond to them when they speak French, they have no reason to make the effort of learning how to speak Turkish. They have no need for it, so they simply don’t do it.
I discovered this simple and powerful concept of exposure and need on Bilingual Monkeys. Maybe it’s applicable to other areas of learning than languages?