You could use the scream on NPC to startle them, and provoke a fight if spammed, or to scare kids, or even badly wounded enemies/animals to have them start fleeing ! (you could then finish them off or let them go, so more RP options).
I mean it surely doesn't take a Dragon Shout to scare a nosy brat.
Also when exploring without having to stop and kill every rat that sees you, you can just scream at its face and it would run away in the bushes, allowing you to properly continue.
Although maybe that would mean including sound detection mechanism from other entities/npcs