The plural of syllabus is syllabi. Or is it syllabuses? Focuses and foci, cactuses and cacti, funguses and fungi: English has a good set of these Greek and Latin words—and pseudo-Greek and Latin words—that might take a classical-sounding plural. Or might not. It kind of depends.
There’s pretension, no doubt, in using fancy plurals: a hangover from the days when class distinction could be measured by the remnants of a classical education. But we’ve all been carefully trained to mock such pretensions (on the grounds, as near as I can tell, that it’s terribly lower class to affect the traits of the upper class). And the most prominent use of such plurals nowadays is for comic effect, puncturing a stuffy occasion.
My favorite appears in one of Jim Butcher’s Dresden Files mysteries, where the detective announces, at a high-toned art gallery opening, that he collects Elvii: pictures of Elvis Presley painted on black velvet. But if we let the comic use entirely devour the serious, what shall we do with nucleus and nuclei, stimulus and stimuli—to say nothing of all the other classically influenced plurals that make an appearance in the mess that we call English: parenthesis to parentheses, or phenomenon to phenomena, or medium to media?
In truth, we object to these only when we notice them. Nobody gets worked up when vertebra increases to vertebrae, or alumnus swells to alumni. If a rule had to be constructed, it would probably involve where the stress falls and, especially, how technical the word’s use is. Philosophers don’t sound pretentious—at least, no more than usual—when they speak of one genus and two genera, any more than astronomers do with nebula and nebulae.
Mockery is not the only pressure on these words, of course. If the plural is better known, it begins to reach back, like a bacterium, to absorb the singular, as data is doing to datum, and criteria to criterion. If the singular and plural appear in different-enough contexts, they can lose sight of each other altogether. Who still hears stigmata as the plural of stigma?
The only real pressure in the other direction these days seems to be the copy editor’s hunger for a settled answer, as though to say: I don’t particularly care whether you pleaded or pled; I just want you lawyers to pick one phrasing and stick with it so I can make my pages consistent. “Descriptivism” and “prescriptivism” are the grammarians’ only apparent choices: Do we make a dictionary of what people do say, or what they should say?
It’s common, in this context, to deride the pedants who constrict language with sterile rules of grammar. The problem, of course, is that there aren’t very many of those pedants left. The recent campaign against the word syllabi appears to have begun on the “Language Log” blog, a fairly representative hangout for grammarians and linguistics types, where some of the descriptivists still seem to see themselves as embattled radicals struggling against Victorian hypocrisy. I’d more readily believe it if America had enough unrepentant prescriptivists left to fill a Volkswagen. Reading the Edwardian-style attacks on school-marm grammar, one expects to come across brave calls for free love, women’s suffrage, and sentimental socialism.
In fact, the copy editors may have it right. What we need is a new prescriptivism, just to balance the books a little. The impulse to lock words down, to make them more consistent, and to use them clearly—isn’t that part of language, too?
The trouble with pure descriptivism is that, in its moral outrage, it refuses to describe half the history of English. Words and usages come flooding in, and then those words and usages get sorted out. We’re deep in one of the inflows, right now, and complaining about restrictions on English is like shouting fire while going over Niagara Falls.
As it happens, syllabus may have originated in Latin through a scribe’s error in rendering a Greek word. At least the Oxford English Dictionary says so, but, as one “Language Log” commenter pointed out, the standard Liddell-Scott-Jones dictionary of Ancient Greek differs on the point. Regardless, the word passed into English from Latin, as a late borrowing, and it seems to have added its –i plural at the same time.