I *think* he means a system of team-chats like is available in many other team-based games (Counterstrike, Battlefield, to name some). Thus, you hit the teamchat key and that opens up a menu of common phrases (nade! defend! om down, attack! etc.) to send to your team, each of which is bound to another key (frequently, the numbers) without affecting whatever you normally have bound to those keys.
People here refer to those as "vsays" because of the voiceovers that are planned to be included with them (as exists in mentioned other example games).