My girlfriend is German, and although she is bilingual, her family are not. We are planning to marry in England and I wondered if there were any "official" translations of the standard (ish) wedding vows, or if we should ask someone to translate them. Also I wondered what the best way to arrange the two languages was - I wondered about having the official say the English, and then someone else repeat the German.
Congratulations on your forthcoming wedding. Why not send out an order of service to your German friends and family in German so when they arrive at the church they will know a little of what's going on?
You could also add some German to the ceremony. Ask everyone who is going to speak at your wedding to write down what they are going to say. You could then have this translated and hand it to your German guests when the speeches are being read. This way they will be able to follow what's going on. You could also have a translator sitting close by to quietly translate what is being said.
I think it would be a good idea to talk this over with your vicar, as he or she may be able to help you.