Audio Emotes
I think the Devs have commented on implementing an in-game voice chat application, and have said they have no plans to do so.
I’m not sure how they would feel about user-controlled audio messages. I know I would probably have such a feature turned off, just like the player instruments. Too many find it hilarious to spam things.
Good luck on your suggestion, though.
Thanks for the thoughtful reply Inculpatus cedo. I have actually thought about getting one of the ArenaNet music devices and volunteer to become audio prompter to an invasion in WvW. Though, a lilting harp just doesn’t do an incoming WvW invasion justice.