Babies are much better at learning languages – any world language – than adults. This window of opportunity, wide open during the first years, will close with time. But is it really a good idea to raise a bilingual or multilingual child? In fact, it depends on many parameters, like the family structure, the parents’ backgrounds, and much more.
A point supposed as an inconvenience from a long time ago is that teaching several languages simultaneously to babies may hurt the primary language. In fact, babies learning two languages have generally smaller vocabularies in each of them. On the other hand, learning two (or more) languages early can bring lifelong benefits later on in reading and writing habits, in the processing of complex tasks, and in overall education.
Another big question to ask is who, in the family, will speak which language with the infant. Should each parent use only one of both languages with the child? Or should both parents speak both languages with the child? Is it necessary to be very strict about it?
