Voice
From RWP Wiki
Voice communication is a feature of Xbox Live that allows players to talk to one another using a headset. The Xbox-compatible headset is known as the "Xbox Live Communicator," while the Xbox 360-compatible headset is known simply as the "Xbox 360 Headset." Voice capability is noted on Xbox game cases but not Xbox 360 game cases, most likely because its functionality is handled by the 360's hardware, as opposed to the Xbox's software.
Thanks to voice communication, players can strategize with their teammates, "talk trash," or simply discuss whatever they wish. Some players even attempt to sing or play music. However, some players use Voice to broadcast obscenities and slurs, as well as to harass other players. All games that support Voice allow players to "mute" other players, which cuts off verbal communication between the muted player and the player who did the muting. Both the Xbox and 360's player review options include options for inappropriate use of the headset.
Most games with Voice support have multiple "channels" for communication: in many free-for-all games, anyone can talk and be heard by anyone else in the game, while in team games, players can only talk to players on their own team. Some games, such as Halo 2, feature "proximity voice," where players can hear a teammate or opponent talking simply by standing in close proximity to their character.
Lack of communication between teams is usually remedied by the inclusion of a pre- or post-game "lobby," where the players from each team can freely talk to one another.