I've played quite a few maps where I've selected a unit and no speech nor a talking portrait occurs. I am wondering how this can be done with triggers, and if not, how this can be done without modding it.
MUTEUNITSPEECH under all players.
E-A-S-Y
go and make a trig with w.e and scrool down on actions and you'll see "mute unit speech"
that simple
Wow, that made me seem pretty stupid. Well then... I know there's no way to replace the unit speech, except by editing the SC Sounds folder, so I'll leave it at that.