http://www.tesnexus.com/downloads/file.php?id=38466
Apparently Bethesda had originally intended for NPCs to talk to themselves when idle and went ahead and recorded dialogue for them before removing the feature prior to release. I'm guessing it seemed weird to have so many otherwise sane NPCs constantly talking to themselves, or something.
I'm actually surprised it took five years to uncover this content and make a mod to patch it back in--I'd never heard of any of this until now. I just wanted to bring it to the attention of anyone here on the forum who hasn't come across it yet.
Actually, the craziness factor of NPCs constantly talking to themselves might be reduced somewhat if regular player-nearby greetings were removed, so the idle dialogues are more like invitations to conversation, I guess.
plz delete thread