There's more to literacy than a high school diploma

As Tina Miller maneuvers a yellow school bus over the highways and byways of Orange County, Fla., she reads the familiar road signs: Stop, One Way, Do Not Enter. Five years ago, Tina couldn't read well enough to get her chauffeur's license.

Tina faced her problem and asked for help. The Adult Literacy League (ALL) at Valencia Community College in Orlando matched Tina with a tutor.

Before learning to read, she was among 23 million adult Americans considered ''functional illiterates'' - people who can barely cope with everyday reading and writing tasks such as addressing an envelope, writing a check, or reading the labels on soup cans.

The number of functional illiterates - a staggering 1 in 5 adults - does not appear to be dwindling, says Lynn Curtis of Laubauch Literacy International (LLI), a nationwide volunteer tutor organization.

Illiteracy, he says, is ''a serious problem - one that is really dangerous for society.'' People who can't read ''get farther and farther away from the rest of society; they become alienated. We pay the price in crime, military (un)preparedness, poverty.''

Conventional illiteracy, a category that includes any American older than 14 who lacks a sixth grade education, is nearly obsolete (.06 percent of the population). But the functional illiteracy rate is much higher - and actually may be increasing, according to specialists in the field.

''Academic certification has nothing whatsoever to do with literacy,'' says Sue White, research associate for a literacy study done at University of Texas at Austin. A high school student ''can take English 1, 2, 3, and 4 and still not be able to fill out a job application,'' she says.

According to the university's Adult Performance Level Project (1975), 11 percent of America's high school graduates can't read well enough to interpret a bus schedule or address an envelope. And that figure does not include the one out of every four teen-agers who never graduates from high school.

Tina dropped out before finishing the 10th grade. She admits she wasn't the most willing student, but adds the school hardened her truculent attitudes.

''My teacher in junior high school used to call on me to get up in front of the class to read. Then she'd make fun of me when I wouldn't do it. . . . She knew I couldn't read,'' Tina says.

She made up for her embarrassment by being a ''big shot'' - but her embarrassment finally led her to quit school.

''I was the type of kid who, if they weren't going to show me how to do it (schoolwork), I wasn't going to do it,'' Tina says. ''But they passed me through school, when I shouldn't have been. And they do it to this day.

But Tina's attitude changed when she was 17, pregnant, and afraid she'd never be able to read to her child. Two years after Tina joined ALL at Valencia Community College, she could read newspapers, her Bible, and stories to her son, Jacob.

The program she joined is one of about 600 volunteer groups affiliated with LLI. The Laubach method, with the motto ''each one teach one,'' teaches phonetic-based reading. The teacher and student meet once or twice a week at a place convenient to both of them.

Like Tina, 1 million teen-agers a year quit high school to become the illiterate adults of the next generation. But the high school drop out rate is just one of many contributors to the problem. Over the years, a number of reasons for continued growth in the illiteracy rate have been named: the influence of television, the deterioration of teaching in public schools, the changes in family structure, and more recently, the influx of non-English speaking immigrants and refugees, primarily from Latin America and Indochina.

But whatever the cause, illiteracy impairs the productivity and saps the self-respect of millions of Americans. The University of Texas study showed strong links between illiteracy and poverty (40 percent of adults with annual incomes under $5,000 are functionally illiterate, compared with 8 percent with incomes more than $15,000).

Says Annette Laico, director of Literacy Volunteers of Washington, ''Think of all the energy some adults have put into their lives covering up the fact they can't read, then think of how much more could be accomplished if they could rechannel this energy.''