iOS: Change language back to English after accidentally changing to a language I don't know
To solve a problem like this, I'd typically go to translate.google.com, type in "General", "International", and "Language", and translate them from English to German. 

Or, sometimes I'm fortunate enough to have two computers/devices side by side, or I simply remember the user interface layout, and I navigate by menu item location.

I changed my iPhone 4 to run in German (Deutsch), and the German words are:

Einstellungen (Settings) > Allgemein (General) > Landeseinstellungen (Country settings) > Sprache (Language)

So just look for those words to navigate through Settings and change back to English.