A triumph of sibilance – yes!

When did yes! get its "s" back? What do you mean, "get it back"? you may ask. It never lost it, not in proper English anyway. Indeed not. But I'm not thinking of the standard yes of "yes and no," but of that emphatic yes! that has become something of a micro-catch phrase in American English over the past 20 years or so.

It's a yes! that used to be yeah! – with a bang, as the exclamation point used to be known in print shops.

When the Red Sox finally broke "the curse" by sweeping the 2004 World Series, the one-word lead headline in The Boston Globe was "YES!!!"

The same affirmation was certainly a scene-stealer in 1989, the year of the movie "When Harry Met Sally." This is the flick with the deli scene in which Estelle Reiner, after overhearing a bravura performance from Meg Ryan at an adjacent table, memorably tells the waitress, "I'll have what she's having."

And at a perhaps more down-to-earth level, "Yes!" is the refrain of "Life's Little Victories," an occasional feature in Keith Knight's cartoon strip, "The K Chronicles" on salon.com.

Researching all these has meant negotiating some nuances among them. The ordinary yeah, for one thing, has a dual life.

In Neil Simon's comedy, "The Odd Couple," Felix establishes the motherhood credentials of the wife who has just given him the boot by explaining how polite their children are. "They speak beautifully – never 'yeah,' always 'yes.' " For Felix, that final sibilant (the technical term for the "s" sound) is the mark of good manners.

But yeah is ubiquitous in ordinary conversation, even on the lips of well-educated people, although it appears far less frequently in print. There's also the yea (rhymes with "hooray") of a cheer – "Yea, team!" This appears in published form so seldom that most people probably think it's written yay.

Trying to establish a timeline for use of phrases like "Our team, yeah!" I ran across a number of instances of yeah online where the long-a yea was probably meant.

The real research find, though, came in the Oxford English Dictionary. It turns out that while yes! is very much a contemporary utterance, it reflects a usage that goes back centuries.

Its background is a little murky, but yes came later than yea, and is, the OED reports, "confined to English." On the other hand, yea has counterparts in other Teutonic languages.

The OED also says that yes was "formerly usually more emphatic than 'yea' or 'ay.' " Which is to say that "yes," half a millennium ago or so, would have had an effect quite like what the Globe was striving for to celebrate Boston's moment of baseball glory.

After 1600 or so, yes replaced yea and ay as "the ordinary affirmative particle," as the OED puts it. But there is another principle of usage at play here: yes as the answer to a question phrased in the negative, "Aren't you coming with us?" "Yes, I am."

(In the King James Bible, "yes" appears four times – in response to questions or statements phrased in the negative. The 1881 revisers missed the nuance and turned them all into archaic-sounding "yeas.")

These two special uses run in the same direction: After all, when you're giving a positive response to something phrased in the negative, you're likely to be emphatic: "Yes, I certainly do know what I'm doing, and I'll thank you to get out of my way."

In language as in fashion, things come in cycles. The triumphal "yes!" of the athlete isn't just saying "yes, we did it." Rather, it's "They said it wasn't possible. But, despite the obstacles, we did it. Yes!"

• This weekly column appears with links at http://weblogs.csmonitor.com/verbal_energy.