As un homme du monde, it is sometimes expedient to drop a foreign phrase smack-dab in media res

Readers have two complaints about my thoughts on the use of foreign phrases in prose and conversation.

Some say it is pretentious to affect a familiarity with a foreign language if one does not indeed have it, and others insist that if one is to use a foreign phrase, one ought to get it right.

I’m not sure that I agree with the first complaint. The only reason I can see for using a foreign phrase, when an English phrase will do, is to give an impression of worldliness and polish.

What’s wrong with that?

Besides, as I said, many foreign phrases have become standard in English, and to use an English phrase in their place is in itself an affectation.

How could one write a detective thriller without such phrases as cherchez la femme and corpus delicti , the first meaning “find the woman,” and the second meaning the body of evidence showing that a crime has been committed.

Like many foreign phrases, corpus delicti is often misunderstood; from a faulty textual inference, it is thought to mean a dead body in a murder case. Certainly a body may be part of the evidence, but it is not in itself the corpus delicti .

I offer that lesson to prove that I am not as ignorant as some readers may think me.

A. D. Grana of Laguna Hills points out that joie de vivre properly means “joy of living,” not “joy of life,” as I said. “But joie de vivre ,” I wrote, “conveys an effervescence that ‘joy of life’ does not.”

I agree with Grana that “joy of living” is a better translation, and is indeed more effervescent.

Will Goodwin, who writes on the pretty blue stationery of the Southhampton Princess hotel in Bermuda, complains that my Latin quotation for “speak nothing but good of the dead”-- de mortuis nil nisi bonum --was not the most effective form.

He says, laying it on a bit thick, “Cher ami. Je ne sais quoi ... je pense, que le phrase re ‘the dead’ is more correctly de mortuis nihil nisi bonum , not nil , which is less than nihil .”

Perhaps he is right. I copied the Latin from Mawson’s Dictionary of Foreign Terms (Mawson/Berlitz). In “Amo, Amas, Amat and More: How to Use Latin to Your Own Advantage and to the Astonishment of Others” (which is what we are getting at here, isn’t it?), nihil is given first, but the book adds: “Nihil is often given as a contraction, nil .”

I plead nolo contendere.

Steve Courso of Riverside complains that he knows no Yiddish words but has to put up with such words as kibitzer, mensch, shtick, nosh and kosher in his daily newspaper. “How can you be surrounded by so many daily writers from all departments who use these expressions freely?” he asks.

Would Courso also expunge such words as bagel, borsht, blintzes, chutzpah, klutz, matzo ball soup and shalom? Oy vey!

Wilfred H. Shaw of Hermosa Beach notes that many foreign phases are corrupted when they come into English, and that some are in that process now.

For example, he cites the French phrases chaise longue and repondez s’il vous plait . A chaise longue is literally a long chair; but we Americans mistake the meaning and call it, rather picturesquely, a “chaise (or chase) lounge.”

Repondez s’il vous plait , which means “respond if you please” (as to an invitation), is usually abbreviated as R.S.V.P., and preceded by the word please, which makes it redundant.

Corbet Hanchett of San Francisco notes that ad nauseam and ad infinitum are useful Latin phrases (to which I add ad absurdum) , and argues that ex nihil, nihil-- “from nothing, nothing”--is more elegant than “garbage in, garbage out.” (More elegant, but not as graphic.)

Konrad Kellen of Pacific Palisades says I erred in equating tit for tat with quid pro quo. Tit for tat, he argues, means an exchange of blows of like severity; quid pro quo means a peaceful exchange. “I give you this (or do this) if you give me that (or do that).” Touche.

Ruth Hinman of Studio City recalls a Latin motto that she once hung up in her husband’s study when he was being ground on at the office. It was Illegitimi non carborundum .

Coincidentally, Illegitimi non carborundum was the motto of my first boss in the newspaper business, and I have always tried to keep it in mind. Its translation I will leave to you.

Anyone wishing to cultivate a vocabulary of foreign phrases may cultivate the books I have mentioned. There are many others, including “You All Spoken Here” (Penguin), which contains such distillations of Southern wisdom as “Don’t hit a hornet’s nest with a short stick,” and “Sleep with a dog and you’ll have fleas.”

Coincidentally, I have received a copy of a pair of cassettes, “Culturally Speaking,” that present the words and translations of 320 of “the world’s most savvy expressions” in French, Italian, Latin, German and Yiddish.

An introduction promises that these phrases will “add sparkle, wit and humor to your daily conversation, and give you a polished and sophisticated air.”

Included are such conversational ornaments as menage a trois, arrivederci, tempus fugit, auf Wiedersehen, and l’chayim. (Producer Marion Forrest says the tapes will soon be in bookstores; meanwhile, they can be ordered from her at P.O. Box 1245, Beverly Hills, Calif. 90213, $16.95 inclusive.)

And always remember: Errare humanum est.