november.sierra,
I don't know about Germany but let's face it, the theory is the same regardless of where you learn to fly. In June, a colleague of mine, who happens to be Hungarian, took his PPL writtens in Belgium (Flemish). He attended lectures which were given in Flemish, used their study material, also in Flemish, backed up by the Trevor Thom series and the PPL confuser. He passed all exams first time.
You may not have access to the exact line of questioning but a sound theoretical base will stand to you regardless of where you acquire it, or who's asking the questions.
BTW, where in Germany are you flying? Best of luck with the exams!