Wait, I've got the best idea.
Seriously..
Make team-chat wavs of like stuff you would say with your team. Fall back, Go go go, Help, Enemy sighted, etc... Players could play them by clicking their icon on a small GUI thing. And if the player chose to hit it for killing someone (enemy down) then the player would click on that. There could be an 8 second delay on sound clickings or something so people don't spam the sounds.
