I played this from a CD for the Mac when I was a kid (which I believe used the TIE Fighter engine), and I remember there being plenty of voice acting. I understand that this is the floppy version, though. Did the DOS CD release have voice acting?

Don't have a joystick at the moment. I will tomorrow, though. Should be fun to give that a try!

If I recall it correctly, Xwing only had spoken dialogue during mission briefing, the one provided by General Dodonna -in Historical Combat- and Admiral Ackbar -Tour of Duty Mission Briefing, and of course during the cutscenes. The in-game engine didn't supported spoken dialogue, you have to rely on the text shown at the communications bar at the bottom of your screen. Tie Fighter was the one with full dialogue spoken for the series. Curiossely enough, XW vs TF also didn't had any spoken dialogue during missions, that was something they reintroduced for Xwing Alliance, the last game on the series.