This is one of the most popular street foods in Sri Lanka. When cooks are preparing kottu, one can hear the clashing of the blades on the bread from the end of the street. A week after I arrived in Sri Lanka, I could recognize the sound right away and usually made my way to it to have a nice, hot plate of kottu.
The dish is popular in Sri Lanka but it might be Indian in origin. Kottu means "chopped" in the Tamil language, so the dish basically means chopped roti and that's what it is.