Hi there,
During my first few weeks here, I had the honor meeting Mr. Rogers (the famous kids' show host) and about learning English, he told me to listen to the NEWS radio and try to write it down (which you are doing now)
So, expanding upon his advice, I would say go to itunes U and listen to some of the lectures there. They have hundreds and hundreds of lectures available from many schools. (It's really cool). From there, you can get a feel of how professors talk. Of course, write something down afterward.
For communications part, you will learn it when you get here.
. Your roommate might be the best way to start. In my case, I told them to correct me whenever I say something wrongly. They did exactly that.
And to make you feel better, I came to the states knowing very few words (most of them food names) and I can't even write. So, I am sure you will be doing great.
Good luck