Actually, I think I can help clarify this thread.
Origin has no built-in voice chat system.
With that said...
If you are hosting or joining a Dead Space 3 game, there is a voice chat system implemented into the game. Not all Origin games support this feature and it only exists on a per-game basis. When a player joins the coop lobby, you will have the option of using voice chat or muting the other player. The voice chat system is voice-activated and there is no option that I'm aware of to change it to a toggle system. If you use another voice chat service such as Ventrilo or Teamspeak, you will want to mute the other player from the lobby as you will not get the oppurtunity to do so unless you rehost/rejoin the game.
As far as I am aware, there is no in-game text messaging feature. As such, if the other player does not have a microphone, you will not be able to directly communicate with the other player in-game unless you press Shift-F1 and use the Origin overlay.
I hope this helps.
