One in a series of occasional articles on the people affected by the No Child Left Behind law.

Mary Bottomley, a reading teacher at Middlesex Elementary School outside Baltimore, led a class of first-graders through a review of words like "dot" and "hot."

But by Bottomley's design, not everyone paid attention. Three pupils sat at a back table with teacher's aide Betty Hylton, who helped them tackle the more-advanced task of writing sentences. Their small hands firmly gripped pencils, and lines began to form: "A pot is hot," wrote 6-year-old Demi Slattery. Hylton patiently offered corrections on spelling and punctuation.

Three days a week, Bottomley and Hylton work as a team at the Essex school, which receives Title I federal funds because of its high-poverty student population. How much longer they'll stay together, however, is being thrown into doubt.

Hylton, formally known as a para-educator in the Baltimore County school district, has a high school diploma and has worked in classrooms for 11 years. Like thousands of teacher's aides across the country, she was hired before Congress passed the No Child Left Behind Act in January.

Because of the law, she will lose her job unless she earns, at minimum, an associate's college degree or passes a state or local test by 2006.

"I like being with children, but I'm going to have to make some changes," Hylton said after the reading lesson last week. "I'm 40 years old. Going back to school is hard."

The move to raise requirements for teacher's aides is among myriad changes outlined in the sweeping legislation but one of the least publicized. The law also gives children in failing schools the choice to transfer and sets a timetable for teachers in high-poverty schools to become "qualified" in their field.

Nationally, there are about 642,000 aides, with their titles varying from school to school: paraprofessionals, instructional aides, educational assistants or, simply, "paras."

Their duties range from helping a special education student follow the lesson in a mainstream classroom to providing individual tutoring to struggling readers. These low-profile support roles, with full-time salaries as low as $11,000 a year, are held almost exclusively by women -- for many, a natural outgrowth of years spent as a parent volunteer.

As a result, aides often lack formal training but possess intimate knowledge of a school and its community.

"The aide is the go-between and the translator between the teacher and the child," said Bruce Fuller, a professor of education and public policy at the University of California at Berkeley. "The rub is, as you try to professionalize these women at the bottom of the labor pool, do you essentially filter them out of the educational labor force?"

Maureen Dreibelbis, 48, worked after high school, married and then volunteered at her son's elementary school in Delaware. When a teacher's aide opening came up, the principal offered her the job. She makes $18,000 a year after 13 years of assisting in the classroom, and worries about being let go if she can't meet the new regulations.

"If I don't pass [the test], I may be out of a job," said Dreibelbis, who has taken college courses but lacks a diploma. "With the economy being the way that it is, I worry about people who graduate with teaching degrees and are willing to settle for being a para, and they'll bump me out of my job that way."

Jerry Wartgow, Denver's superintendent of public schools, praises the intentions of No Child Left Behind while striving mightily to follow its demands. Wartgow's district has 70 high-poverty, or Title I, schools, and 2,500 of its teacher's aides are out of compliance, he said.

"We have so many people to get up to speed," said Wartgow, a former community college administrator who is working with former colleagues there to set up training programs for the aides. "It's a huge challenge, but we're seriously trying to accomplish it."

Like siblings who must follow a parental rule but may interpret it differently, each state has the freedom to design ways to comply with the new federal requirements for teacher's aides by 2006.

Nebraska education officials, for example, are considering creating a state test for their aides. California, with its 1,000 school districts, and Kentucky will leave the testing option up to local superintendents, as the federal law allows. In Wyoming, the Laramie County school district is offering a $250 stipend to teacher's aides who possess the college credits or pass the local test this year.

Maryland, Virginia, Arizona, Tennessee and 16 other states plan to use a test called ParaPro, which measures reading, writing and math skills and the ability to help teach those subjects to children. Designed by Educational Testing Service, the company that puts out the SAT, the test is available online beginning this week and will be offered in a pencil-and-paper version in January, ParaPro coordinator Inez Bosworth said. Other testing companies are developing similar exams.

In the District, officials are surveying aides to determine how many comply with the law. A task force will investigate a range of options, including a testing program, to help them meet the requirement, said Paul Ruiz, the school system's chief academic officer.

For some states, complying with the law is more complicated. In Alaska, access to higher education is limited by a shortage of highways and by the harsh climate. "We have a considerable problem in addressing that particular part of No Child Left Behind," said Harry Gamble, a spokesman for Alaska's education department. "We'll probably try to seek some allowance from the federal government to be flexible on their timetable."

Any teacher's aide hired into a Title I school after the passage of No Child Left Behind must meet the requirements immediately. The unions who represent aides are galvanizing their veteran members to make sure that they are aware of the changes.

Iona Holloway, a teacher's aide in Louisiana and an officer with the National Education Association, said she has attended meetings at which anxiety and misinformation have run rampant. One common complaint was that there is no government money available to help pay for college courses. But federal officials said the money to train aides exists within teacher grants, Title I funds and other avenues.

The federal Head Start program offers evidence that meeting a tough requirement is possible. In 1998, Head Start was given five years to get half of its teachers to achieve an associate's degree. A status report last year showed that 46 percent of local programs had already met the standard.

Holloway, the aide in Louisiana, said that despite the pressure and stress, there is a benefit to the new law. "It finally recognizes that I am an important part of a child's education. I am not an ancillary."

Betty Hylton, a para-educator at a Baltimore County school, helps Demi Slattery and other students practice their vocabulary skills.