I'm 18, he's 16. One of those guys who has been hurt by bad friends and stuff, I talk to him about it, he seems fine now. He never starts the conversation but talks alot when i start, quite submissive. He doesn't express himself well to me, while i'm introvert, I either talk to you or not, he just is weird, very sometime-ish. he tries to use sarcasm but being the quiet observer i am, i don't get impressed easy so i just be like," Ok, nice try...." But he then tries to do be sarcastic multiple times in row, making it less effective than it already is and annoying me because I can't have a proper conversation. BTW we knew each ohter from high school, but we are busy in school so won't get any real life contact till school is done.
^^^ Just tell him, "Can we have a proper conversation?" If he uses sarcasm, tell him to cut it with the sarcasm. But, it's confusing what you mean by sarcasm and how that means he's terrible at communication.