Gah - a solution with more questions. – EntropicLqd

From Unreal Wiki, The Unreal Engine Documentation Site

Causes the dude to say something, but only when he's looking directly at this actor. Used in many maps where the dude can comment on his surroundings ("Did someone slaughter a goat in here? Seriously, I wanna know.")

[edit] Properties

float CanSeeViewCone 

Tightness of view cone. 0.1 is very tight, 1 is very wide

Sound SoundToPlay 

Say exactly this when you see this trigger