Open the "matanui" folder then open the "SetLang" folder. Windows users run the file "SetLang.exe", Mac users run the file "SetLang.app", and Linux users run "SetLangENG.sh" for English or "SetLangDEU.sh" for Deutsch. Alternately, replace all of the contents of the file "getlanguage.txt" inside the "matanui" folder with "&language=eng&" (without the quotes) for English, or "&language=deu&" (without the quotes) for Deutsch.