Ditto... I wouldn't punish him either. It's happening in class, it needs to be DEALT with in class. Staying quiet and listening is a learned skill. And it's one that needs to be taught IN the environment that it's used in.
Another thing to consider: When my son was in school we made a deal... He would NOT get in trouble twice. Period. That way he could feel free to talk with me about *anything* that happened, have a shoulder to cry on, or an ear to bend, or be able to ask for advice without being afraid of being punished for something that he'd already been punished for. We called it Double Jeopardy. Once my son got that I was serious about not getting him in trouble twice, he REALLY started to share/confide with me. It was SO soooo useful.