I's still Alpha, but there is planned for Radio, whispers and shouts to help deal with Chat channels. There was a radio discovered in the game but how will some of this work- is not defined yet.
Man, I can't imagine how cool it would be to have a group of people coordinating through radio chatter and then the other group hears them get overrun... What would also be cool would be to add interference in some places to make conversation that much more tense..