It is possible to talk to Ash Slaves like normal NPCs if the player manages to interact with them without being detected first. When not trying to kill the Nerevarine, the Ash Slaves appear to be quite preoccupied with the arrangement of their furniture. In fact, their dialogue seems to imply that the furniture is talking to them and that they simply want it to be quiet. This explains why the furniture in Sixth House bases is always arranged in bizarre ways.