„A warm smile is the universal language of kindness.“ William Arthur Ward
If nothing works, smile! Normally that helps. This morning I asked a guy to clean my shoes on a square around the corner. He smiles at me, pointed to my shoes, made hand gestures to show that I had to put the other one on the wooden block. He didn’t say good morning or good-bye as he assumed I could not speak his language – which is not fully true. I can say what he didn’t 
That brings up a point that I always emphasize while learning languages: shut up and listen! Don’t talk too much, and if you do, ask questions. Especially English mother-tongue speakers have the tendency to assume that most people know something in their language, which is mostly correct.
But then they don’t even learn good morning and good-bye in other languages. They help others to improve their English which is nice too but won’t help them.
So, be quiet and shy and smile!
