Several Harpy NPCs in WoW can communicate with the player, like the the Witchwing Harpies when they are aggroed and the quest in Mount Hyjal where you have to interrogate Marion Wormwing.The problem is that harpies don't seem to be very eloquent creatures, or at least unintelligible to the human ear...
Allow me to illustrate my point. Go here, click "Play", "Attack", and "Death".
Also, the Raging Worgen Hearthstone card doesn't have any quotes that are "intelligible to the human ear".