Saving for the next time I teach “Intro to English Study.”

It’s all well and good to sing “The Ballad of Sweeney Todd” to the tune of “Hallelujah,” but why can’t you do it the other way around? For that matter, why does it work only when you limit yourself to the first two lines of the song? Why can’t you make the whole tune fit?

Generally speaking, the answer is boring: most song lyrics don’t fit any particular poetic meter. They don’t need to. On the page, a poet must rely on meter alone to convey rhythm and structure, but if you bring music into the mix, well, rhythm and structure are what music is. When song lyrics do fall into an identifiable poetic meter, the phenomenon is rare enough to be ripe for comedy, as we’ve just seen. —Frankie Thomas, The Paris Review