My guess is that it is similar to several ??? in Chinese (particles that are added to sentences to indicate the mood that the sentence was spoken in, like, "its obvious", "is that ok?" ...) Anyway, I know a few Chinese who add "ma" to the end of their English sentences, because "ma" is one of those particles. The only similar thing I have encountered with native English speakers is the "eh" some Canadian's add to the end of their sentences.