Have you tried setting the default language of Steam to English? This helped me for my games, as I too prefer to play in English instead of German. At least when it comes to non-German games. You probably need to verify the game data afterwards or re-download the game.
If that doesn't help, you could try to download the game from Stardock directly. Use the same login-info as for the forums.
I hope either option works for you.
