If my experience as an orthoepist has taught me anything, it’s that most people who get paid to talk on television or the radio know diddly-squat about pronunciation. But because these people are professional broadcasters or entertainers, the rest of us tend to assume, to our pronunciatory peril, that they do. This is how beastly mispronunciations are often spread: from the slipshod media to the unsuspecting masses.

Yet, once in a great while, someone who makes a living smiling in front of a camera or spraying saliva into a microphone does know something about how words ought to be pronounced, and like those “ironic points of light” that “flash out wherever the Just exchange their messages,” we’re surprised and enlightened by a dazzling moment of on-air orthoepy.

For example, last July on the Late Show with David Letterman, Katie Couric gently but firmly corrected Dave’s pronunciation of preternatural. Although Dave insisted, with the blustery, overbearing assurance of the philodox, that the first syllable was pronounced pret as in preterit, Katie held her ground and (despite mangling the spelling of the word) showed Dave and the world that the proper way to say it is with a long “e” as in pretext: pree-tur-NACH-ur-ul. This is the only dictionary-sanctioned pronunciation, a fact that a much-deflated Dave had to admit. (It has not yet been confirmed whether he ate any of the crow that Katie’s handlers offered him during the commercial break.)

More recently, Martha Stewart, during one of her regular appearances on NBC’s Today Show, made orthoepic broadcasting history by informing the world that the Italian appetizer bruschetta is correctly pronounced broo-SKET-uh, not broo-SHET-uh, as Meredith Vieira confessed she had always mispronounced it.  Of course, if the imperious Martha had told Meredith that “pie” was properly pronounced “pee,” no doubt Meredith and the rest of the world would have believed her.

In this case, however, Martha was not only redoubtable but also right, because the consonant blend sch should sound like sk, as in school, the musical term scherzo (SKAIRT-soh), and maraschino, which in the cultivated speech of the cognoscenti is pronounced ma-ruh-SKEE-noh, not ma-ruh-SHEE-noh. The many speakers who, like Meredith Vieira, have always thought bruschetta was pronounced with an sh sound in the middle may have been misled by false analogy with the toothsome Italian ham, prosciutto, which even poor Meredith knows is pronounced proh-SHOO-toh.

But even the formidable Martha Stewart gets it wrong sometimes, proving yet again that an authority on any given subject is not, by extension, also an authority on how to pronounce words related to that subject. I can’t tell you how many times I’ve heard doctors, lawyers, college professors, research scientists, and other specialists of all stripes mispronounce words pertaining to their specialty — sometimes in the capacity of an on-air expert. And the fearsome Martha, homemaker extraordinaire, is no exception, for, I regret to report, she mispronounces cumin as KYOO-min.

This trendy variant, with what is sometimes called a y-glide for the u (as in cubic or humor), and another popular variant, KOO-min, without the y-glide, are speculative pronunciations based on how the word is spelled. But as a peek into the Oxford English Dictionary reveals, cumin is but one of many spellings for this venerable word, which dates back to the 9th century. This long line includes cummin (still recorded in some modern dictionaries), commin, comin(e), comeyn, cummyn, and comyn, all of which pointedly do not suggest a KYOO- pronunciation with a y-glide. And indeed, as a little historical research also quickly reveals, the traditional pronunciation of cumin until the late 20th century was KUM-in (as in “Hold your horses, I’m comin’”). Not surprisingly, KUM-in is the only pronunciation listed in the Oxford English Dictionary and the first listed in the American Heritage Dictionary, which you can hear at Wordnik.com.

Dictionary editors, or lexicographers, are honor-bound to list any pronunciation in widespread use at a given time, so most current dictionaries now recognize KYOO-min and KOO-min. But the Orthoepist, mindful that his job is to give judicious advice on what is correct, is duty-bound to reject what is fashionable for what is traditional and cultivated. Therefore, this is my ruling on cumin: Ignore misguided Martha and other foolish foodniks who say K(Y)OO-min and say it as it has been said for hundreds of years: KUM-in.

[Charles Harrington Elster, Wordnik’s Orthoepist (and token prescriptivist!), blogs about pronunciations. His tenth book, The Accidents of Style: Good Advice on How Not to Write Badly, has just been published by St. Martin’s Press.]