Doomspeak is a [bardic] feat from Champions of Ruin with the following benefit:
You can spend one of your bardic music uses to utter a string of crass and appalling epithets and curses at one enemy within 120 feet. The intended target must be able to hear and comprehend your damning remarks. A target that fails a Will save (DC 10 + your character level + your Cha modifier) is cursed with a -10 penalty on attack rolls, saves, ability checks, and skill checks for 1 round. This is a supernatural, necromantic effect.
But do you use a standard action to activate it like bardic music, or is it a free action because it's based on speaking? It consumes a use of bardic music, but like Haunting Melody I believe that it isn't bardic music itself, and would thus be a free action, 'piggybacking' on the insults you are hurling as a free action. On the other hand, it's a "supernatural effect", so does that make it a (Su) ability and thus a standard action by default?
As a side note, does Dragonsong work with Doomspeak?