Absent dialogue issue/bug

Hey friends!

I've just started playing BG1 again. I wanted to hang out with some of my old fictional friends again, but imagine my disappointment when I discovered they'd all become mute! I've reached chapter 3 with no random dialogue among NPCs. I then installed the tutu mod and restarted (exporting my character from the first game, in case it's relevant) and the issue has continued thus far in my new game as well.

I've played the game before, so I know there's meant to be more dialogue than this. It was all over the place the first time, and I didn't get much further than this before seeing it.

If it helps, I'm playing the game in single-player mode. My party had Imoen, Viconia, Minsc, Dynaheir and Edwin the first time, and Imoen, Viconia, Kivan and Ajantis the second.

Also, I had a look around, and I see this has been raised in a couple of other threads, but the issue wasn't resolved in either of them. I'll link to the ones I found for convenience:
http://forum.baldursgate.com/discussion/9263/serious-npc-dialogue-bug
http://forum.baldursgate.com/discussion/8323/no-dialogue

Thanks for your time!