The key, and I think this applies to any language, is not NOT BACK DOWN. Some things will be hugely painful, if you back down you just defer the pain. The Germans will want to be polite and helpful (and practise their own English), don't let them.
Some HNers will know about the Israeli language courses after the war, when Israel had a seven-digit number of immigrants, hardly any of which spoke modern Hebrew. Modern Hebrew is an invented language, BTW, so "hardly any" is not an exaggeration. The model that worked was three-week full-time courses where ONLY modern Hebrew was spoken. They didn't let anyone back down: Students went without food until they were able to order in a restaurant where the waiters were helpful but spoke no foreign languages (usually late on the first day).