Imagine that in 2009 England’s cricketers, per impossibile, regain the Ashes. You can’t? Neither can I. Yet, just imaginably, it might happen. That’s what per impossibile means. It’s Latin by origin: per, through; impossibile, the impossible. But is it by now English?

I’d firmly say not. But the status of many such phrases is less clear. Status is indubitably English. But status quo or status quo ante (literally, the state of affairs in which, previously...)? De facto, yes, but neither de nor facto on their own. Ad hoc, yes, but post hoc, propter hoc (after this, [therefore] because of this)? What about ex post, or ex post facto, as economists and high-falutin’ journalists love to write? Each word there in itself is pure Latin: ex (out of or from); post (after); facto (that which has been done, the event). Yet neither phrase, two-word or three, is even imaginable Latin; they’re modern concoctions. So they must be English? Not to me, they aren’t.

Many single Latin words have joined English unchanged, though often with a new sense: verbatim, quondam, nil, id (it), ego (I), item (likewise), animus (soul), rebus (literally, by things in Latin, but in English a sort of pictorial puzzle), fiat (literally, let it be done), imprimatur (let it be printed). I’d smuggle quiz into that list: I suspect, though most dictionaries don’t, that it came from the old schoolboy game of holding up something — a biscuit, say —and shouting Quis? (Latin for who?), ie, who wants it?, and giving it to the first boy that shouts ego.

Many abbreviations began as Latin words: eg (exempli gratia, for the sake of an example); ie (id est, that is); viz (videlicet, short for videre licet, it’s allowable to take a look at); a.m. and p.m.(ante and post meridiem, midday); DV (Deo volente, God willing); QED (quod erat demonstrandum, what was to-be-demonstrated). Whether spelt with full-stops or not, these, certainly as spoken (“ee-djee”, eg), are plainly English, no longer Latin.

Sometimes we’ve shortened the Latin: nem con (nemine contradicente, nobody speaking against); the pros and cons (from pro, for, and contra, against; though the anti of the pro and anti factions is from Greek, not Latin). Sometimes we’ve taken in whole phrases: I’d certainly class a non sequitur (literally, it does not follow) and a quid pro quo (what for what?) as English phrases. But I’d hesitate over persona non grata; and I’d definitely say no to mutatis mutandis (those things having been changed that had to be changed) and the full quod erat demonstrandum.

Does it matter? In practical terms, not at all. Most languages use words drawn straight from others, and unless it’s overdone, who cares? And some Latinisms anyway are dying out, as the teaching of Latin is. Yet Latin even now influences their pronunciation.

We still pronounce most Latin words or phrases as Victorian Britons did, ie, as if they were written in English. Though even British public schools long ago switched to today’s more “international phonetic” pronunciation of Latin, we still say ver-bay-tim, not ver-bah-tim, ree-bus, not ray-bus, fy-at, not fee-at. Most strikingly, for prima facie (at first look), we say pry-ma fay-shee, not pree-ma fa-ki-eh.

Or do we? Modern dictionaries now bless both im-pry-may-ta and im-pree-mah-ta. Some people say day fakto, not dee. I myself vary between fy-at and fee-at. And many of us are simply baffled by prima facie. This is partly because our Latin pronunciation itself has changed, but more — few people today learn Latin anyway — because today’s English-speakers have met “international” spelling. With one newborn Latin name, indeed, they’ve gone the whole way and out the other side: as the nasty germ clostridium difficile spreads through British hospitals, doctors have shortened it to c. diff. and say see-diff; but some broadcasters say diffi-seal, as if the word were French.

That’s what I’d call a reductio ad absurdum.