Maybe the other guy is just scared, too
Sometimes (or most times) it’s daunting to speak a new language to its native speakers. You might be worried that they won’t understand you or you’ll be laughed at. I hate to tell you that these things will probably happen, but if you get laughter, it probably won’t be malicious.
In cultures where there is a definite idea of foreigners (e.g. some places in Asia or the middle east), your potential audience may be just as freaked out as you are. From the moment you start approaching, they need to think about possibly having to speak a language they don’t know at all, and that situation is worse than yours. Obviously this is not the only reaction, but I’ve come across it often enough. I’ve seen Chinese people say no or that they don’t understand before the foreigner can even say anything.
You could always run away and find someone else to talk to in these instances, but the best idea is to at least try. Worst scenario is that you will have to resort to miming and drawing pictures, but in the best cases, you will succeed and the other person will realise that maybe you’re not so scary after all.