Point 1:
Interesting thing. I don't know if it's related.
As usual, I don't recall the details. This is what I think I remember.
There are different species of birds that look the same, but have different songs. You can take an egg from one species and have it nurtured raised by the other species. It will never learn the songs of either its own species or its adopted species. If bird songs are like languages, and if I have not misremembered or misrepresented, this might indicate that that there are cultural and genetic components to language (specifically grammar).
Point 2a:
Another thing I almost recall. I read somewhere (not a particularly reliable source, but I don't remember where it was for sure) that there are cases of kids who are "raised" (read 'abused') by putting them in a room and giving them no outside influences. The sad thing is that even after these kids are rescued, they never quite master their new language.
Point 2b:
Possibly corroborative anecdotal evidence. One of my best friends is this Korean fellow who was adopted by Americans. It's been a very long time since we discussed this, but I seem to recall he was adopted some time between 5 and 8 years old. In any case, this guy is really smart. But you wouldn't be able to tell it. He can't speak Korean any more except for a few words. And his English is terrible. Simple sentences are fine, but anything more complicated and it gets progressively difficult to understand what he's saying. A mutual Indian buddy was continually correcting K's English, but it just never sunk in. I interpret this as something traumatic happening to him during the time frame when he would normally be acquiring linguistic stability.
k
