If you’re coming for a short visit, I’d highly recommend you try to learn a few useful phrases. The first being, “Ich bin ein Amerikaner. Sprechen sie Englisch?” That means “I’m an American. Do you speak English?” This will work best with younger people who are still very close to the language as it’s mandatory in German schools for at least a few years. Speaking with older people, you’ll find them either not speaking any English and if you’re traveling through the former East Germany, they might still remember Russian.
Duolingo is an excellent tool to help build some confidence in being able to learn extensive vocabulary to at least get you started in a short conversation or to ask