I. Structure

The form of the rhyme is more complex than it first sounds. The words are usually sung, and melody is fairly simple, universal among children. The rhyme scheme remains a-b, c-b throughout, and the stanzas are organized into couplets. However, meter is the unifying element of the rhyme, maintaining the order of this semmingly inconsistent and unconventional ditty.

The rhythm is a trimeter, but the singer accents the correct syllables so lines end with emphasis, or punch. However,the arrangement of the accented syllables allows the singer to touch on, but not actually say, taboo words. Here are beginning stanzas of two Versions of the rhyme, the oldest one and the newest one, side by side (my emphases):

Even though there different numbers of syllables in the two Versions, the metric effect still works because it does not matter how many unaccented syllables there are. This effect is known as sprung rhythm. Here the accented syllable, in this case "Hell," falls at the end of the last line of the stanza. The listener's ear then loses the "O" from "Hello" at the beginning of the next line, so he/she ends up hearing simply "Hell."
The effect of the rhyme depends on the trimetrical arrangement of the lines. Throughout its evolution, this rhyme has been a way for children to practice saying taboo words without actually saying them. I remember singing the song and feeling the rush of excitement in knowing I could sing the rhyme in front of my teacher and not be punished for swearing, because I wasn’t actually saying “hell” or “ass,” I was simply accenting a syllable. This song allows one to experiment with how it feels to say naughty words; it allows manipulation of language and according social norms. This rhyme, while it feels like a subversive activity, is also good practice with language skills.