In wizard mode, if you possess some other creature, you can talk to yourself for some very funny lines.
If you are near two or more NPCs and want to chat with them, and then press "." to choose yourself as a target, you talk to yourself - apparently, this also abuses intelligence.
Also, tell me what you will, but kicking chests when they stand against the walls gives a higher chance of opening them. I kicked a big chest to no avail the whole bloody corridor, and as I kicked it against the wall, the lock broke.
Edit: One more: Petrus' wife #4 is blonde... she has more charisma than the other ones, but half the intelligence