Sa, su, si.

She had less than two seconds to pick the pair that matched the sound in the headphones.

She picked. Wrong.

Another combination appeared and she picked again. Wrong.

Day after day she failed the test.

In the United States only two months, the studious 15- year-old from Cuba wanted nothing but success. But Martinez felt lost, swallowed up in the crowds of Leto High School.

In Cuba, her school had been small, the classes intimate. She didn't have to rush from room to room every 50 minutes. The teachers were the ones who switched.

``Here is very different,'' she says later, pausing to formulate her next words, her face looking tired and sad. ``Here I feel very, very small. I feel I'm invisible.

``I'm trying to learn English, but it's very hard. I ask people, `What is the teacher saying?' And they look at me like they don't know what I'm saying, like I'm nothing.''

Leto, in Town 'N Country, is a swirl of the children of Mexicans, Cubans, Colombians and Puerto Ricans. Then there are the newly arrived Venezuelans, Hondurans, Peruvians, Ecuadorians, Dominicans and Haitians. Some were among the middle class in their countries; others lived in poverty.

Many have little in common, but they share the struggle of grasping at lessons in a language that to them is foreign. They share the frustration that can make punching a cash register more appealing than sitting in class. They share a sense of being isolated in a fragmented community.

By 16, thousands have given up on the American dream. Less than 69 percent of Latino students graduated on time in Hillsborough County, according to state records for 2002-03. That means nearly a third of the Latinos who were ninth-graders four years earlier were sidetracked along the way.

For black students, the graduation rate was 65 percent.

For whites, it was 83 percent.

Facing Obstacles

The obstacles blacks and Latinos confront aren't parallel. Though Latinos faced serious ethnic discrimination in Tampa's early days, it eased as they prospered. Black people, meanwhile, continued to be barred from mainstream society until the mid-1960s. The effects of those Jim Crow laws linger with the malevolent persistence of radioactivity.

But as the face of the Latino community changes, the problems of Latino and black children converge.

Both are the victims of the racist assumption that because their skin shade is dark or they speak with an accent, they are thieves or drug dealers. Both are more likely than white children to live with parents who didn't graduate from high school. Both are at risk of seeing themselves as outsiders, not welcome in the larger community.

Yet the success of the larger community hinges largely on the success of these students. More than half of Hillsborough County's students are classified as minorities. Many were born here to immigrants who arrived since the 1960s. But many others came only last year or the year before. And more come every day.

Martinez was an A student in Cuba, but here she battles to keep her head above water.

``These kids fail not because they lack cognitive ability,'' says Claire Noguerol, who counsels Leto students struggling to speak and learn in English. ``The problem is they can't follow along in class. They don't know what the teacher is saying.''

Noguerol works at a round kitchen table covered in a light blue table cloth, a set she brought in to give her office the feeling of home. A box of tissues sits at the edge of the table for the children who come to her in tears.

The county enrolls all students in the classes appropriate for their grade level, regardless of how well they know English. Martinez takes world history, literature, geometry. Also, she and others not proficient in English take special language classes.

``It's sink or swim, and many sink,'' Noguerol says.

Noguerol has started a program at Leto that allows students struggling in English to learn from teachers with special training. They teach in English but speak slowly, use universally understood gestures and refrain, for instance, from using phrases they know will be confusing.

``I can't tell you how much apathy these kids feel, like nothing they do matters,'' she says. ``I know a lot of kids feel that, but I really see it in the Latino kids.''

Trying To Keep Up

Martinez copes by focusing almost obsessively on her classes.

In the lunchroom on a recent day, surrounded by students who bunch together by race and by nationality, she eats alone, quickly, then walks fast to her first afternoon class, geometry.

She rushes to her locker, then to class. She arrives early. Sitting in the front row, she looks straight ahead as the teacher calls students to the board to work out geometry problems.

Behind her, kids draw pictures, throw wads of paper at one another, beg fellow students for completed work sheets when their turn comes at the board. The teacher's sharp call for attention is met with snickers, which prompt a louder demand, which gains perhaps 30 seconds of order. Then the playing resumes.

Next is English and the dreaded exercise Martinez failed the time before, and the time before that. The idea is to teach the sound of consonant- vowel combinations. Sa, re, cu, ti. This is critical for reading. It's been near-torture for Martinez.

``I just wanted to quit,'' she says. ``I felt so bad.''

But not as bad as the day she was asked to read aloud in world history and a girl behind her giggled. ``I just put my head down and cried.''

``Language acquisition is a painful process. It's so personal,'' Noguerol says. ``With some people, when their emotions are heightened, the ability to express themselves in a new language sort of shuts off.

``No learning happens under these circumstances.''

But on this day, Martinez heads smiling from her English class to world history. She finally passed her test, picking the correct consonant-vowel pair in the allotted time.

On her way to history, she looks for one of her language teachers, but she's away from her office. This teacher has gone so far as to sit with Martinez in some classes, to help her keep up.

Martinez gets this kind of attention because she begs for it, Noguerol says. Most other students don't.

``They're too shy, or self- conscious, or proud,'' Noguerol says. ``They're the ones we need to worry about.''

Lindsay Peterson