Speaking Polish

Today I had a vagrant approach me at the bus stop.  He started talking to me, but I didn't have a clue what he was saying, and was pretty sure I didn't want to know.  I just said "Nie rozumilam" I don't understand.  He seemed puzzled and kept talking.  So I said "Nie mowie po polsku"  I don't speak Polish.  At that point he looked skeptical but left me alone.  There is a certain irony to saying in polish "I don't speak Polish"!