In the book Where Mathematics Comes From, by Lakoff and Núñez, I came across this sentence:
All human beings, regardless of culture or education, can instantly tell at a glance whether there are one, two, or three objects before them. This ability is called subitizing, from the Latin word for “sudden.”
Spanish speakers are likely to recognize in subitizing the word súbito, which developed from Latin subitum, the past participle of subīre, the predecessor of Spanish subir. Now, the fact that subir means ‘to go up’ is often puzzling to English speakers who learn Spanish, and perhaps to Spanish speakers who think about it, because we’re used to associating sub with ‘under,’ as in submarino/submarine and subterráneo/subterranean. The explanation is that *upo, the Indo-European ancestor of Latin sub, actually meant ‘up from under’ as well as ‘under,’ As a result, Latin subīre meant not only ‘to come or go under,’ but also ‘to come or go up to’ and ‘to spring up.’ It’s that sense of springing up, which of course takes place quickly, that gave Latin subito, and therefore its Spanish descendant súbito, the sense of ‘sudden(ly).’
Alongside subitus Latin created the longer adjective subitāneus, which Spanish has borrowed as subitáneo, and which the DRAE defines (somewhat circularly, because a definition isn’t supposed to use another form of the word being defined) as ‘Que sucede súbitamente.’ Vulgar Latin turned subitāneus into the slightly shorter *subitānus; that evolved to Old French sodain, which Middle English borrowed, and which has become sudden in modern English.
Let me close with a little coincidence. While I was writing the first part of this post on April 25th, I walked into another room where the television was on and tuned to a news channel. As I kept walking, I glanced at the television screen and saw video of a crowd in Rome that had gathered early for the canonization two days later of Pope John Paul and Pope John XXIII. One of the people in the crowd was holding a sign saying “SANTO SUBITO.” Though you might be tempted to translates that as ‘sudden saint,’ in Italian subito has taken on the sense ‘immediately, right now.’
© 2014 Steven Schwartzman