Gross me out, I mean, Valley Girls was, like, ohmigod, it was last year, fer sure! I mean, get a life! Say what?

Say "bitchin" and "grody" and "tubular." Say "excellent" and "totally" and "awesome."

Say it ain't so.

But it is.

There's a whole new way of talking among teen-agers, thanks to 14-year-old Moon Unit Zappa's hit record last summer titled "Valley Girl," a rambling monologue that parodied the vocabulary and elocution of affluent teen- agers who frequent shopping malls in Southern California's San Fernando Valley.

"It was more of a spur-of- the-moment thing," says Zappa, daughter of '60s rock cult figure Frank Zappa. "(My father) woke me up in the middle of the night and said, 'Come on down to the studio and just . . . babble.'"

So she did. The result was a surprise hit record, and teen-agers everywhere began talking that talk.

Like any youth fad, adults soon analyzed and mined it. Letters began appearing in the pages of the (London) Times Literary Supplement this winter debating the etymology of "grody" (which means disgusting), and newspapers chronicled Val-Girls' fashions (mini-skirts, ruffled blouses, gold chains) and haunts (shopping centers). The CBS television series "Square Pegs" stars Valley teens, and shopping centers have sponsored Valley Girl contests. (At one such contest at a mall in Stamford, Conn., a three-way tie was broken when a 14-year-old finalist took the stage a second time and won by remarking, "This is it, like, coming up the stairs so many times. Give me a royal break.")

"What's really happening here is we've got a way for kids to identify themselves as kids," says Victor Golla, an associate professor of anthropology who specializes in languages and society at George Washington University. "To take my own household, there is clearly a cultural and social difference between the adults and kids. It's not a matter of us representing different ethnic backgrounds or anything like that. But by virtue of being kids, the teen- agers in this household have been kind of assimilated into a sociocultural network that we adults by definition can't be part of."

It would be as difficult for an adult to enter that world, says Golla, as it would be for a non-Moslem to enter Mecca.

"And the slang is picked up and transmitted through this social network, and, of course, it is transmitted by the record industry, radio and other kinds of communications networks that didn't exist 20 or 30 years ago," says Golla, who nonetheless argues that mass communication is not solely responsible for the spate of slang, status and fads in which youth sometimes finds itself awash. "The creative act that doesn't respond to some kind of social need isn't going to be picked up."

Clearly, Valleyspeak struck a responsive chord.

Jennifer Jones and Halley Finkelstein, two students at the National Cathedral School, use words such as "massive" to express delight, as in "a massive guy" or "a massive stereo system." Synonyms include "totally," "awesome," "cosmic" and "mega," as in "mega-repulsive." Rapture is expressed as "cosmic to the max." "Ex" is an abbreviation of last summer's premier compliment, "excellent!"

On the negative side, there's "repulsive" and "sick me out" or "gross me out." Said sarcastically, "wonderful" and "good job!" are put- downs, as are the expressions "That has got to go!" and "What's your problem?"

"Any in-group will have its own limited vocabulary," says Carl Bode, a professor of English at the University of Maryland who keeps an eye on fads. "In the government, they said 'indicate'--why the hell don't they say 'said'? Then you realize that in government reports 'indicate' is so blurry, you can't pin it down the way you can 'said.'"

Other times, other government workers have coined their own jargon peculiar to times, such as "third-rate burglary," "inoperative," "stonewalling it" and "expletive deleted." Stockbrokers talk of "profit-taking," "bargain hunting," "sitting on sidelines," "technical rally," "backing and filling," "Fed watching" and "the bottom line." The entertainment industry, home computer fans, journalists and engineers all have their own jargon that serves as a kind of shorthand for insiders, just as Valleyspeak does for teen-agers.

"There are probably two origins for the impulse to make slang," says Philip Herzbrun, an assistant professor of English at Georgetown University. "One is differentiation and the other is exclusivity . . . It usually springs from a group of people who want to differentiate themselves from others-- such as gangsters, musicians and soldiers--or from those who want to have a kind of insider's language that can't be shared because it's the exclusive property, the badge or shibboleth of the people who use it. It changes radically . . . Once, a slang word would last about a generation, but now, yesterday's slang is the stalest thing on earth in three or four years."

Indeed, Sandy Poole, Jeanne Duymovic and Tracy Putnam, three students at Bethesda's Walter Johnson High School, say Valley Girls were yesterday's news, though the watershed record by Zappa did leave a legacy of slang.

"'Mega' was last year," says 17-year-old Poole. This year's (or last week's) word is "tenacious," as in, "He's one tenacious guy." A guy who is not tenacious, that is to say, who might be homely, can be summed up with the words "sin," "death" or "twink." The perfect put-down: "Get a life!"

Sex and slang have always gone together, and Valleyspeakers have their special vocabulary, too. Sexual intercourse is sometimes referred to benignly as "getting together." Or you can ask your closest friend who arrives late to a party: "Were you being noisy?" An attractive girl (or, as some Valley guys put it, a "babe") is "nice" or "fat" or "a freak." A handsome boy is a "fox."

If you're neither a babe nor a fox, if you are over 20 years old, well, ohmigod, do us all a favor. Like, don't try to imitate Valleyspeak. Pronounce "cool" correctly; don't overreach by saying, as Valleyteens do, "ku-el." A final word of advice: If you must go to a shopping center, do your business and get out. Because, like, you know, you don't even know how to speak the language. Fer sure.