How do you say...what?

We're in the Flanders area of Belgium. I was expecting to speak French, or even German, and it appears to be Dutch with German, French and a bit of English mixed it. I feel bad just speaking in English without making effort in Dutch. I need to just say "Hello" in German and let it be, though I don't know what it is. I do how to say "thank you" in German, that's easy. I learned no and Christmas tree.