Waltzing Matilda is an Australian "bush ballad" composed by Christina Macpherson with original lyrics by Banjo Paterson. And if English is your second language, don't doubt your comprehension over this song. There is so much dialect here, that even as a native English speaker, I have to read a translation to understand the subject matter. Also, don't get hung up on the word, "rule" here. These rules are broken all the time and still produce great melodies. And of course, these rules are specific