One of the giant steps forward that colleges are taking these days is a step backward. They're trying to teach students how to write.

This may sound a little wacky to anyone who hasn't been on campus in the last decade. But it represents somewhat of a revolution at many universities which, in their rush to become "relevant" in the Vietnam war years, decided classes that did things like teach people how to write English were passe.

Now many of the same places are madly dashing backward. Dozens of universities have set up special writing skill centers. Classes to teach enginerrs, chemists, business majors and pre-law students to write straightforward declarative sentences are springing up all over the country. Cornell University has even named a dean of writing.

It's partly an acknowledgement of a serious student problem, a reaction to the same type of pressure that forced the "back to basics" movements on elementary and secondary schools. It's also one of the hottest educational fads going.

"The issue emerged about four years ago. Basically, there was considerable unhappiness with the quality of student writing," says Dr. Malcolm Sillars, dean of humanities at the University of Utah. "We came out of the late '60s with the highly permissive notion that there shouldn't be required courses, that students should be free and all that."

"Many of us were undercover in those days," he said. "Now we're coming out. I think it's all part of a broader movement back to more basic requirements and more traditional approaches."

While moving backward, the colleges are trying to sound progressive. The old terms "remedial writing" and "bonehead English" are out. So are English composition classes with a grey-beard professor at the blackboard. "Skill development centers," "tutoring labs" and "drop-in centers" are in. So is "peer tutoring."

At the University of Marland, which required 12 semester hours of English for graduation 15 years ago, students now must take only one three-hour class. Those who score low on the verbal sections of entrance exams are subjected to something called "modular learning," which concentrates on things like learning to write paragraphs. At the University of Wisconsin, they're using audio-video tapes to teach how to write research papers. And a consortium of Ivy League colleges is toying with the idea of teaching English composition on computer terminals.

The programs all are aimed at correcting a basic problem: students are not writing as well as they used to.

"The writing decline is not only marked, but it's massive," says Dr. Robert Farrell, dean of writing at Cornell University. "This is not a national problem, it's an international one. My colleagues in Sweden and Germany are experiencing the same thing we are here."

"We get a lot of people who come to us as burnt-out cases. They're convinced they can't write," he says. "The most encouraging thing is students realize they need these skills and they want to do something about it. It's not that they're stupid or incompetent. It's just they haven't been given the opportunity to write."

The reading and writing ability of high school juniors and seniors has dropped steadily since 1964, according to standardized test scores. Almost every one has a theory on why. One of the easiest is that high schools stopped teaching writing.

"Careful writing has about gone out of style," declared a recent report on the decline in scores by high school seniors taking the Scholastic Aptitude Test, which is used by colleges in determining admissions. Enrollments in basic English courses in California high schools, it reported, dropped 10 per cent between 1971 and 1974; enrollments in English composition classes plummeted 77 per cent. "Increasing reliance in colleges and high schools on tests requiring only the putting of Xs in boxes contributes to juvenile writing delinquency," the report said.

The full force of the decline took years to sink in at collges, many of which were contributing to the problem. Reports of students being worse rather than better writers after four years in college are widespread.

At the University of South Carolina, writing lab director Larry Hewland reports scores of juniors, seniors and gradudate students coming to his lab haven't written a report or term paper in three or four years.

When the university dropped requirements in traditional subjects like history and philosophy in the early 1970s, professors in those fields found it hard to attract students, he says. So they watered down the standards. Written papers were expendable.

"The university has been concentrating more on numbers than quality," he declares. "There are some classes where students get credit for just sitting there without ever taking a test or writing a paper. If a professor says he's going to require a paper, students drop out."

"The pessure for numbers is building," Howland adds. "It's like Vietnam body counts. If you've got 50 students, they tell you you should have 100."

Ironically, the university's writing lab, which offers one-on-one tutoring, has grown by leaps and bounds. So have labs at other universities. Some campuses like the University of lowa have had these labs for decades. Scores of others have jumped on the bandwagon recently. "It's something fashion has dictated all over the country," Howland says.

Each college seems to have its own twist. Cornell has a writing workshop for freshmen who have severe writing problems, writing seminars for more advanced students, and a drop-in center at the school library where students can get advice on how to write papers. Its business, urban planning, engineering and hotel management departments have new writing classes of their own.

At Maryland the faculty senate is to vote this week on adding a writing class for college juniors - something that the colleges of business engineering and agriculture at the University of Wisconsin already have done.

With help from the National Endowment for Humanities, which is spending $1 million on writing programs this year, Rutgers, the universities of Colorado and Vermont and eight California colleges have launched programs to teach high school teachers how to teach writing. These are modeled after a highly successful Bay Area writing project at the University of California at Berkeley.

It's hard to tell where the campus writing boom will turn next. Already signs of wear are showing. Few of the new writing instructors, for instance, have been given full-time, tenured jobs, and the long-term status of their programs is uncertain.

"It's all great as far as it's gone, but it's not far enough," says Carol Freeman, director of writing at the University of California at Santa Cruz. "The most important thing is that we have to make a long-term committment to writing."