http://www.bungie.net/Forums/posts.aspx?postID=11111719&postRepeater1-p=1
You can turn it of basically, You have to go to Headquaters and then opitions, it's in voice I think. Edit: NVM says above.
First, you may have noticed that all ingame communication with enemy players is prohibited in Ranked matches. This does mean you cannot talk smack, but it also means somewhat less verbal abuse, and greater concentration on team communication. Our focus in Ranked hoppers is combat and competition, clean and simple. Humping, however, is significantly improved.
In Social hoppers, an option exists in your Voice Communication settings to impose similar restrictions. However, it is turned off by default. Our focus in Social hoppers is on interaction with other players, and voice is part of that. Not everyone enjoys this interaction, though, and prefer to talk only to their team and party. The voice option is Matchmaking Voice > Team and Party. If enabled, you will only hear (and be heard by) members of your team, and members of your party. Of course, if your party members are divided onto enemy teams, you will only be able to communicate via proximity voice.
You can turn it of basically, You have to go to Headquaters and then opitions, it's in voice I think. Edit: NVM says above.