When Caroline Kennedy managed to say “you know” more than 200 times in an interview with the New York Daily News, and on 130 occasions while talking to The New York Times during her uninspired attempt to become a hereditary senator, she proved, among other things, that she was (a) middle-aged and (b) middle class. If she had been a generation younger and a bit more déclassé, she would have been saying “like.” When asked if the Bush tax cuts should be repealed, she responded: “Well, you know, that’s something, obviously, that, you know, in principle and in the campaign, you know, I think that, um, the tax cuts, you know, were expiring and needed to be repealed.”

This is an example of “filler” words being used as props, to try to shore up a lame sentence. People who can’t get along without “um” or “er” or “basically” (or, in England, “actually”) or “et cetera et cetera” are of two types: the chronically modest and inarticulate, such as Ms. Kennedy, and the mildly authoritarian who want to make themselves un-interruptible. Saul Bellow’s character Ravelstein is a good example of the latter: in order to deny any opening to a rival, he says “the-uh, the-uh” while searching for the noun or concept that is eluding him.

Many parents and teachers have become irritated to the point of distraction at the way the weed-style growth of “like” has spread through the idiom of the young. And it’s true that in some cases the term has become simultaneously a crutch and a tic, driving out the rest of the vocabulary as candy expels vegetables. But it didn’t start off that way, and might possibly be worth saving in a modified form.

Its antecedents are not as ignoble as those of “you know.” It was used by the leader of the awesome Droogs in the 1962 novel A Clockwork Orange, by Anthony Burgess, who had possibly annexed it from the Beatnik Maynard G. Krebs, of Dobie Gillis. It was quasi-ironic in Scooby Doo by 1969, and self-satirizing by the time that Frank Zappa and Moon Unit deployed it (“Like, totally”) in their “Valley Girl” song in the early 1980s. It was then a part of the Californianization of American youth-speak. In an analysis drawing upon the wonderfully named Sonoma College linguist Birch Moonwomon's findings, Penelope Eckert and Norma Mendoza-Denton phrase matters this way: “One of the innovative developments in the white En­glish of Californians is the use of the discourse-marker ‘I’m like’ or ‘she’s like’ to introduce quoted speech, as in ‘I’m like, where have you been?’ This quotative is particularly useful because it does not require the quote to be of actual speech (as ‘she said’ would, for instance). A shrug, a sigh, or any of a number of expressive sounds as well as speech can follow it.”

So it can be of use to a natural raconteur. Ian McEwan rather surprised me when I asked him about “like,” telling me that “it can be used as a pause or a colon: very handy for spinning out a mere anecdote into a playlet that’s full of parody and speculation.” And also of hyperbole, as in “She’s been out with, like, a million guys.”

Its other main use is principally social, and defensive. You will have noticed the way in which “uptalk” has also been spreading among the young. “Uptalk” can be defined as an ostensibly declarative sentence that is uttered on a rising note of apology and that ends with an implied question mark. An example: the statement “I go to Columbia University?,” which seems to say, “If that’s all right with you.” Just as the humble, unassuming, assenting “O.K.” has deposed the more affirmative “Yes,” so the little cringe and hesitation and approximation of “like” are a help to young people who are struggling to negotiate the shoals and rapids of ethnic identity, the street, and general correctness. To report that “he was like, Yeah, whatever” is to struggle to say “He said” while minimizing the risk of commitment. (This could be why young black people don’t seem to employ “like” quite as often, having more challenging vernaculars such as “Nome sane?”—which looks almost Latin.)