As Northern Virginia became home to more immigrant families in recent decades, Fairfax County officials say they started programs to teach English as a second language at every school — about 200 of them. Except one.

The holdout was the region’s hallowed magnet school, Thomas Jefferson High School for Science and Technology, where many assumed that steep admissions standards rendered such a program for English language learners unnecessary.

But next year, at the behest of the school’s teachers, Thomas Jefferson — often called TJ — plans to hire its first instructor to cater to a growing number of students who thrive in math and science classes but sometimes struggle with English.

The decision to hire the half-time teacher has reinvigorated a debate about TJ’s mission — namely, how heavily the school’s admissions policy should favor math and science standouts over well-rounded applicants with superior reading and writing abilities.

“It sounds kind of like an oxymoron. How can they not know the language and still get into TJ?” said School Board member Elizabeth Bradsher, who added that the need for English-language services has raised questions about the school’s admissions process.

TJ is a powerhouse when it comes to math and science. In 2009, 25 of its students were admitted to the Massachusetts Institute of Technology, and hundreds got into other top schools. That reputation has attracted a flurry of recent immigrants from South Korea, China and India, some of whom learn about TJ long before landing in the United States.

News reports in Korea tell of the school’s accolades. The country’s embassy devotes a section on its Web site to describing TJ’s admissions criteria, translated into Korean. As of last year, students of Asian descent outnumbered white students at the school. Black and Hispanic students made up less than 4 percent of the student body.

Applicants must be residents of one of six Northern Virginia school districts during their eighth-grade year in order to gain admission as freshmen. TJ is the only selective, specialized high school in Fairfax; there is no equivalent school that focuses on the humanities.

“We are a math, science and technology school, and we might get students who excel in those areas but still have some language troubles,” said Evan Glazer, the school’s principal.

Fast-paced classes

TJ is revered by many not only for its traditional academic strengths in math and science but also for its all-around academic rigor — as a springboard for top students with a diversity of interests. That dynamism is reflected in the school’s faculties in English and social science departments, which feature rare combinations of Ivy League graduates, lawyers and PhDs.

But some of those teachers have complained to the administration and the School Board in recent years that a number of students struggle to keep up with fast-paced classes when they are reading and writing-intensive.

“I tell my teachers at the beginning of every school year that English is my second language, that sometimes I forget the articles and that I might need extra help,” said senior Yena Kim, 18, who moved to the United States from South Korea when she was in fifth grade. “I want to give them a sense of who I am.”

In the absence of a designated English language instructor, Kim grew accustomed to asking her friends and teachers the same question: “I know how to say this in Korean, but how do you say it in English?”

Citizenship a question

Some argue that the issue is not only whether such questions — common at most Northern Virginia public schools — are appropriate at TJ but also whether the school’s limited spots are being given to foreign nationals.

“I would hope that the administration is ensuring that all of these kids are U.S. citizens,” said Gary Bottorff, a former director of corporate and community relations for the Thomas Jefferson Partnership Fund, the school’s fundraising arm, from 2006 to 2010.

The school’s admissions committee does not ask about the immigration status of applicants.

Clues to proficiency

TJ’s admissions test includes a verbal section and two essay questions, which officials say helps them gauge students’ grasp of the language. “If a student did have a deficiency, we would be able to identify that deficiency in the admissions process,” said Tanisha Holland, the school’s director of admissions.

But last year, school officials designated 13 of its 1,764 students as having limited English proficiency, meaning that their English skills were still in need of improvement. Others were not formally designated but, according to school officials, could have benefited from additional help in English.

The students in need of additional language support at TJ are mostly those who received basic services in earlier grades and need further support in order to keep up with TJ courses, said Teddi Predaris, director of Fairfax schools’ Office of Language Acquisition.

Yet at the highly competitive school, where students agonize over how to squeeze as many high-level classes into busy schedules, some may decline such services, Glazer said, if they conflict with advanced science or math classes. He said such such conflicts are likely. In the past, when teachers have broached a student’s language difficulties, some parents have been quick to sign waivers declining extra help.

If there is no demand for a conventional course in English proficiency, Glazer said the instructor would serve as a resource specialist who meets students by appointment.

Struggling classmates

“If you tell students that they can’t take certain math classes because they need to take an [English proficiency] course, this whole thing is going to be a disaster,” said Sin Kim, a senior, who emigrated from South Korea when he was 13 and said he polished up his English skills before coming to TJ. Like some of his classmates, Kim came to the school for its math and science curricula.

He took Advanced Placement calculus as a freshman but still had other advanced math courses to choose from after completing the conventional high school offerings. Those courses have come fairly easily for Kim, and he does fine in English now, even if it’s not his favorite subject.

But he knows that some classmates who arrived in the United States a few years after he did still struggle.

“They might know how grammar works. They know a lot of words. But getting comfortable writing just like a native — it just takes longer.”