Fatana Ansari's trip to a Fairfax County school-registration desk last month began when a rocket fired during a fight between warlords tore through the roof of her house in Kabul and killed three of her neighbors.

Fatana was a young child then, and her family paid smugglers to help it flee Afghanistan. With her mother and older sister, she walked across the countryside, staying in villages along the way. Finally, carrying only a bag of clothes, they crossed the border into Pakistan.

A decade later, the shy 14-year-old refugee sat in a tidy Falls Church area classroom quietly puzzling over math problems. Her younger sister read aloud a story about children eating ice cream in a park, and her brother talked to a teacher about whales. One of the nation's best school districts was trying to decide where Fatana -- and hundreds of other children who speak little or no English -- belongs.

Tomorrow, four months after entering the United States, Fatana will step into Key Middle School in Springfield and more deeply into the culture of her new home -- a moment she is anticipating with a mix of excitement, curiosity and teenage jitters. She wonders whether she will make friends easily and whether other girls also will wear hijabs around their head and neck. She worries about her halting English.

Her mother, Masooda Ansari, has some advice for her. "The opportunities are here," Ansari said in Farsi, with her brother translating. "If you want to become a doctor, you can become a doctor. If you want to become a bum, you can become a bum."

Fatana, her brother and sister, all fluent in Farsi and Urdu, are among about 1,500 new students beginning school in Fairfax County this fall who will have to learn English even as they are learning science and math. Students in the program called ESOL -- English for Speakers of Other Languages -- make up the fastest-growing segment of the school district's student body, increasing 70 percent since 2000 to a projected 22,868 students this school year, in a student population expected to number about 166,000.

Last year, about half the limited-English students were from families whose incomes made them eligible for free or reduced lunches.

As Superintendent Jack D. Dale begins his tenure in the region's largest school district, ensuring the success of such students as the Ansaris is among the district's -- and Dale's -- greatest challenges. Under the federal No Child Left Behind law, the success of each school is measured by the performance of smaller groups that include students with limited English and poor children.

When the Fairfax County School Board announced Dale as its choice in the spring, some questioned whether his experience as superintendent in Frederick County, a fast-growing but much less diverse school district, had prepared him. Dale's predecessor, Daniel A. Domenech, who spoke no English when he came to the United States from Cuba as a child, was a strong advocate for immigrant and poor children and launched programs that provided extra classroom time at the lowest-performing schools.

Fairfax School Board member Tessie Wilson (Braddock) said she is confident Dale is up to the task, but parents will be watching.

"I'm sure there will be some concerns among the ESOL community because he is taking over from someone who was himself an immigrant and comes from that background," Wilson said. "But that doesn't mean Jack won't be just as good."

Already there are signs that Dale is reaching out to the minority community. He spoke at the first meeting of J.E.B. Stuart High School's Hispanic Parent Teacher Student Association last week, praised the students and teachers and encouraged parents to stay involved.

"Comprendo poquito Espanol," Dale, who said he studied Spanish in high school and college, told the crowd of more than 100 people -- "I understand a little Spanish."

Dale said he shares Domenech's philosophy and noted that Frederick, although smaller than Fairfax, has begun to see an influx of children who don't speak fluent English. Still, Frederick's total limited-English enrollment, 650 students, is less than half the number of ESOL students who will arrive in Fairfax this year and under 3 percent of Fairfax's entire program.

Frederick's program came under scrutiny in 2001 after a former teacher filed a complaint with the U.S. Department of Education alleging that students with limited English were denied adequate services. The district beefed up services, including changing the tools used to test the math skills of such students.

Last year, Dale said, Frederick began a program in four low-performing schools, two of which had high numbers of poor students and children with limited English, that called for longer school days, smaller class sizes and summer programs. "I don't know any way to accelerate children's learning other than provide them more time with qualified people," he said.

Several educators said they agree with that formula, but just as important is understanding the cultures and personal stories of their students. Fairfax students speak more than 100 languages. The day the Ansari children signed up for school, new students also came from Kenya, Mexico, Korea, Spain, El Salvador and Somalia. Spanish is the predominant first language among limited-English students, followed by Korean, Vietnamese, Urdu and Arabic.

Francisco Millet, who headed Fairfax's ESOL program before heading to the District this year to become an elementary school principal, said he would watch television news to predict from where his next wave of students would come. Vietnamese refugees flooded the area in the 1970s when they fled their war-torn country, and families from El Salvador came in the 1980s to escape civil war. In the months after Sept. 11, 2001, the number of children from Pakistan jumped.

"You can look at the hot spots and say, 'That's where our children will be coming from,' " Millet said. "You know that some of them have been through hell, and the fact that they are here and safe and going to school is a major accomplishment."

Apart from the extra attention required by children who have endured war and poverty, there has been an increasing awareness of subtle cultural differences that dictate changes in teaching techniques.

In some countries, schoolchildren are drilled in memorization but might have little experience in critical thinking, Millet said. Other times, parents might appear uninterested in their children's education, but in reality they come from a place where it would be rude and disrespectful to question a teacher.

For the Ansari children, the biggest adjustment might be their newfound freedom and resources. As Fatana goes to Key Middle, Ratib, 11, and Madeeha, 10, will attend Forestdale Elementary, and the eldest, Fatima, 18, will take adult education classes to earn a GED.

In Pakistan, the children could not venture outside alone. In their school, students stood each time a teacher walked into a room, and the children could talk only to their teacher, not to each other. Fatana, who wants to become a heart doctor, said she grew frustrated because girls were allowed in the science laboratory only one period each week at her school in Pakistan. Most of the time, it was boys only.

Fatana has spent the last weeks of summer enthralled by the simple freedom of riding a bicycle around her Springfield neighborhood.

But last week, sporting a glittery "girls rock" T-shirt that was a gift from a cousin, she said she's ready for school. "I'm nervous, and still happy," she said. "I want to study here."

While Fatima Ansari, 18, second from left, will take courses to earn a GED, her siblings, Ratib, 11, left, Madeeha, 10, and Fatana, 14, will enter Fairfax County schools tomorrow. Ratib, left, Fatima, Fatana and Madeeha Ansari are fluent in Farsi and Urdu, and they soon will be learning English as new students in Fairfax County.Masooda Ansari, rear left, has told her children, Ratib, left, Fatana and Madeeha, who are about to start school, "The opportunities are here."