So I just bought this game again on GOG since I wanted to have a DRM-less version that wouldn't complain about steam.dll through reinstalls, anyway - in both iterations the trapped haunters have no voices when I click on them during missions! I verified the files are there for ones like the weather witch etc, but they don't play back in game.

I know it's not a problem with the codec because the intro sounds play (from the snd files in ghostdata > voices)
the tutorial voices don't play either, and originally this caused me to think the game was completely broken because I was accidentally going with the recommended team on the first level; it wouldn't let me click on anything; yet I wasn't getting any voice feedback about that.

Has anyone else had this problem? I'm running the game from Windows 10 and I've tried different compatibility options...

you could try to reinstall the game or install direct x 9. beyond that i have no idea what you can do.