Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
To my knowledge I've only done this once, and I ended up waking myself up. I have been present to hear others chat it up in their dreams and it can be pretty entertaining. Even more fun is to have a whole conversation with someone when they are clearly more in the sleep realm than the awake one. When you ask them about it the next day they have no idea what you're talking about. Good times.