This counterintuitive relationship between the popularity of a word (its rank in a given vocabulary) and the number of times it appears is described by something called Zipf’s law, an observed statistical property of language that, like so much of the best math, lies somewhere between miracle and coincidence.1 It states that in any large body of text, a word’s popularity (its place in the lexicon, with 1 being the highest ranking) multiplied by the number of times it shows up, is the same for every word in the text. Or, very elegantly:
