Oddly, I have never once thought to question what faces really provide the voices for the Dawn of War games' assortment of space bastards. Did I think there was really an ork behind a microphone somewhere? Did I truly believe there was a man who naturally spoke like Patrick Stewart x1000? Of course not, but a testament to good voice acting is when you don't think "oh, that's just a guy pretending to be an Eldar." In the below video, Relic show just who's providing the snarls, hisses and achingly earnest exposition in DOW2: Retribution. While some performances are better than others (that sure is a lot of North Americans doing British accents), for the most part it's enormously impressive. Particularly, you can't fault either the gusto or the very visible effects upon the faces of those who make the noise of war. For instance, the lady above - take a guess who she plays?
Tattershaw Tatasciore can make noises no human being should be able to make.