Haven't used Paltalk in years (too many late nights, at the time, no Linux support, etc.) but I've just tried the web based Paltalk Express on Linux.

Their Flash application would not let me log in (the password entry box wouldn't accept any characters after entering a user name) but I was able to able to resolve that by using a 64 bit beta plugin from Adobe
here

I've got playback sound but I don't know about the mic - I can't find any means of testing it. Other than that, I'm finding it impossibly slow (although sound is not breaking up), entering rooms hit and miss (and sometimes it will pop up telling me it has failed only to open the room) and I've once got stuck on a cycle of getting logged out, attempting to log in again and getting prompted again to log in before I've had a chance to type anything. I'm not impressed.