How can i tell he likes me?

I like this guy and im not sure if he likes me or not. im pretty shy, and he's a sorta popular skater. We're in one of the same cl together and he looks at me sometimes, and when ever i catch him he looks away. my friends say he looks at me when ever we're in large crowds too. He also acts pretty strange around me when he's with his friends. The only thing keeping me from thinking he likes me is that we NEVER talk except when its absolutly nessacary, and if he does his voice goes an octave higher then usual. ...If he does like me then why doesnt he talk to me?