The game should contain both languages, German and English. I'm not sure how to change the language and whether the setting in the first step while installing the game also affects the ingame language, but try to select English as setup language.
If that does not work move to the options ingame and search for "Sprache" to select a different language.
Bis denne, Han Solo
Driving is life, I live to drive! - Rennspiele / Racing Games