Go to your Profile, then click "Account Related Settings" (or whatever it is in German, but it should be the first link in the box on the left of your screen.)
When you've done this, there will be a type-in box with your forum name in it, and another box next to it that should say "Sprache."
Click this drop-down, and click the one that says "Englisch."
Then, scroll down and click the button at the bottom of the screen that says "speichern."
(Keep in mind, these words may be slightly off, since I had to use an online translator. However, the buttons I described will be in the same places.)
