What we're doing wrong

If you look at it logically, children don't actually acquire their first language, they invent their own language. For their invention to work, it has to be pretty close to what everyone else around them is speaking, so it's usually going to be recognisable as their first language, and is likely to be fairly close to what their parents speak, at least when they're talking to their parents, although it's likely to be a bit further away when they're talking to their peers.

Not, of course, if their parents are immigrants, or if their parents spoke a pidgin and they are speaking a creole. Or if the children are deaf, the language is sign language and their parents are hearers and not fluent signers.

The problem for adults, and by that I mean anyone over at least about six, is that rather than allowing them to invent a language, we're trying to force them to use an existing language. This is not how Chomsky's lad works. This is one reason why most second language learners fail.

Whatever you say about Norman Chomsky, and a lot of people do, his idea about language being innate seems to make sense. That and his politics. His ideas about universal grammar seem to be utter nonsense. The notion of language being a separate special way of learning may not make sense though. It is more likely a part of social knowledge, hardwired into the brain, and in turn created by that brain.

But that may just be Vygotsky.