How much does the child need to be exposed to language use correctly?

According to a lot of research, the rule of thumb is that children must get around 30% wake time of their language exposure.

According to a lot of research, the rule of thumb is that children must get around 30% wake time of their language exposure to become proficient in the language. Sounds about right when you first think of it. Bilingual children don't often have 50/50 exposure to both languages