Geh? What?

Ok, the title's a bit enigmatic, indeed.
So I have a question.
Been learning Japanese since September 2007, and as time goes Im starting to feel that im learning two different languages hehe.
Different (and a bigger) written vocabulary, and a different speaking (hearing as well of course) vocab..
So, is there anyone who encountered the same thing.
Don't get me wrong, im not searching for a solution, as they will overlap anyway when I reach my goal, its just curiosity, yes, I'd love to know if this thing is common.
I suspect that kanji has a role in it, but not only kanji. Well, cause I spend most of my "Japanese hours" grinding vocab, kanji and watching raw programs, so there's not much detailed grammar, no need for that.
Hoping for a diagnose, thank you. : D

So.....what was your question?

Japanese is Japanese. Learning another language will seem like more than it appears to be when in fact it is. But I never thought The speaking and writing were 2 different languages or anything of the such. I just wish I could retain and comprehend better.

Well, its just that my verbal and written knowledge of Japanese overlaps less and less, and the question is if anyone encountered a similar thing.