Fred Madden, in Jabberwocky (Summer/Autumn 1988), calls attention to a chapter titled “Popular Follies of Great Cities,” in Charles Mackay’s classic work, Extraordinary Popular Delusions and the Madness of Crowds (1841). Mackay tells of various catch phrases which sprang up suddenly in London. One such phrase was “Who are you,” spoken with emphasis on the first and last words. It appeared suddenly, “like a mushroom. . . . One day it was unheard, unknown, uninvented; the next day it pervaded London. . . . Every new comer into an alehouse tap room was asked unceremoniously ‘Who are you?’ “
Lewis Carroll; Martin Gardner. The Annotated Alice, The Definitive Edition. New York, W. W. Norton & Company, 2000. Chapter V: Advice from a Caterpillar; note 2 (p. 48).