Three little children, none older than four, get on a Manhattan bus (the 86th Street Crosstown) and sit down. Soon the usual recorded announcement comes over the PA system: “Please exit through the rear door.” The children immediately start repeating the sentence, bouncing it back and forth to each other like volleys on the tennis court. One child even alters it slightly by substituting /l/ for /r/ in the penultimate word so that the sentence comes out, “Please exit through the real door.” The children have a good laugh over this innovation but then go right back to bandying the original.
Why are these juvenile speakers of American English so enamored of the language of the announcement? Because of its prosodic structure, to wit: the sentence consists of a perfectly good trochaic line, with a stressed anacrusis and a spondee in the last foot.
From such perfectly prosaic material is poetry born on the lips of a child.