Well, It’s Like the Meaning Has Changed : Language: The word can be used as a ‘discourse marker,’ as well as for emphasis and to stress a point of special importance in a sentence.

You are in a mall. There are two 13-year-old girls standing next to you. They have blond hair and braces. They are both probably named Jennifer.

“So this guy comes up to me and he is wearing a purple shirt and I’m, like, that is so gross,” you overhear one of them say.

Your mind races. What does she mean?

Was “I’m, like, that is so gross” what she was thinking at the time? Or is she reporting what she actually said? And if she is, did she use like in place of “I said something like” because she cannot remember exactly what words she used and is just summarizing the gist of her comment? Or is she using like in place of say--in which case, why is she using a confusing word like like at all?

It gets worse. You eavesdrop as the pair stop to look at a “Save the Whales” poster. “A whale is like a fish,” one of them says. Again, your mind spins. Does she mean “A whale is LIKE a fish,” as if to set up the conclusion, “But it is not, it is a mammal”? Or does she think that a whale is actually a fish and is using like not to mean “something like” but in a completely different sense as a point of emphasis. As if to say, “A whale is, like, a FISH!” in the sense that “That guy’s shirt was, like, PURPLE!”

This multiform usage of like is an integral part of teen speak, a complicated dialect that might have remained one of life’s intriguing little perplexities.

Luckily, however, linguists have turned their formidable talents to this question, and we now know far more about non-standard uses of like than ever before. We know its demographics. We know about the baffling and ingenious ways it is used by the young, and we have some idea about how it started and where it might be going.

In fact, researchers recently stumbled on a wholly new use of like , employed to incorporate quoted dialogue into speech without the cumbersome “he says” or “he thought”--a development of potentially huge significance in the centuries-long evolution of the English language.

“The grammaticalization of like as a quotative complementizer is a natural historical development for the spoken channel, which allows the speaker to retain the vividness of direct speech and thought while retaining the pragmatic force, but not the syntactic complexity, of the indirect mode,” two celebrated linguists, Suzanne Romaine and Deborah Lange, conclude in a recent essay in the journal American Speech.

What they are saying is that it, like, helps people speak more vividly. Which is, like, sooo important.

The standard use of like , of course, is as a preposition: “He smells like a barn.” A similar but slightly less common usage is as a suffix describing resemblance: “He smells barn-like.”

The use of like as what linguists call a “discourse marker” is surprisingly complex and multifaceted. It also can be used for emphasis and to “mark” or stress a point of special importance in a sentence. With a simple change of inflection, “He is, like, mad,” means that he is very mad instead of sort of mad.

It also can carry a rich emotional nuance. The use of like in “Could I, like, borrow your sweater?” said San Diego State University linguist Robert Underhill, allows the speaker to hedge, to politely distance herself, “softening the request and, at the same time, shielding herself in the case of denial.” It is the same as “You wouldn’t mind terribly if I borrowed your sweater, would you?”

There are other likes, of course: the ironic like, the unusual notion like and on and on. There are even international analogues. Swedish adolescents, for example, use komma --the verb for “to come”--just as American youngsters use like.

These nuanced uses of the like discourse marker have been growing steadily since World War II, and are now so numerous and complex that they are understood only by several million junior high school students and a handful of academics.

The truly cutting edge use of like , however, has emerged only in the past decade or so. Linguists call it the quotative like, used as an introducer of reported speech and/or thought: “So I’m, like, that is so cool. And he’s, like, not.”

What, exactly, does that mean? The answer is very complicated. First, the quotative like is not a simple substitute for forms of the verb say. Said or say are used to report speech directly, “He said, ‘Let’s go,’ ” as well as indirectly, “He said that we should go.” The quotative like is used only in the present tense, and it blurs the boundary between indirect and direct quotation. “He’s, like, let’s go” is thus somewhere in the middle between “He said” and “He said that.”

This usage is oddly gender-specific: Whereas like as a discourse marker is used heavily by young men, the quotative like is almost the exclusive property of teen-age girls.

The reason for this, according to Georgetown University linguist Deborah Tannen, is that girls of that age are primarily “interested in shifting friendship networks, in who said what to whom and what everyone felt like.”

As a result, they fill their speech with huge amounts of dialogue, far more than boys of the same age or women of any other age. What the quotative like allows them to do is to put all that they hear and think into the most dramatic of conversational forms: an active, present-tense mode. When they get older and rely less on reconstructing dialogue in their speech, they gradually drop the quotative like and rely on like as a discourse marker.

Far from being an annoying teen-age linguistic tic, the quotative like actually may be part of a much broader and sophisticated literary-linguistic trend. It may, like, be hugely symbolic. Like, it may even be post-modern.