Their heads bent over the magazine, teenagers Yi Sun and Aileen Leung took turns reading aloud an article on fashion designers.

As they giggled over the photos of the models, Aileen identified a sash in English to Yi, who emigrated from China last year.

Then Yi took her turn. "Here's a word," she said to Aileen, a Chinese American born in the United States, "Shi shang. Fashion."

For two hours on Saturday mornings, about 250 recently arrived Chinese immigrants and American-born Chinese students gather in the cafeteria of Robert Frost Middle School in Rockville for a one-on-one tutoring session.

The program, sponsored by a Chinese American parents group, is the largest in the county in which students teach other students English -- although in some ways the immigrants are doing as much teaching as they are learning.

Outside of these Saturday gatherings, the two groups of children, who share the same ethnic background but are separated by language and culture, don't regularly socialize at school.

Aileen, a 17-year-old senior at Wootton High School in Rockville, said teaching Chinese immigrants helps her connect with her heritage. She can speak conversational Mandarin, but in their tutoring sessions she has learned science and slang words from Yi.

"Even though I was born in America, part of me is still Chinese," Aileen said.

Yi, a 15-year-old sophomore at Walter Johnson High School in Bethesda, said having a fellow teenager as a tutor is very helpful in practicing English.

"They act like Americans, but they know some Chinese terms," Yi said. "It's easier to understand them."

Montgomery County's Chinese are a diverse group. Many families have lived in the region for generations and have children who speak little Chinese. Others have emigrated from mainland China, Taiwan or Hong Kong in recent years, seeking better jobs and educational opportunities. Some are researchers for the National Institutes of Health in Bethesda; others work in restaurants.

More than 28,000 people of Chinese descent in the county were counted in the 2000 Census, an increase of 63 percent since 1990. They are the largest subgroup of Asians, who make up about 11 percent of the county's population.

In the school system, Chinese speakers are the second-largest group, behind Spanish speakers, in the English for Speakers of Other Languages program. More than 650 ESOL students speak either Cantonese or Mandarin dialects of Chinese.

The Chinese American Parents and Students Association started the tutoring program 14 years ago with 30 participants, but it now fills the Robert Frost cafeteria with students from kindergarten to high school.

Brigitta Dai, a retired special education teacher's aide, said she helped start the program because of her memories of her eldest daughter's difficulties learning English when the family emigrated from Taiwan 30 years ago. She said that after one year in the sixth grade, her daughter still had trouble distinguishing the letters "n" and "u."

Dai and her husband spent countless hours after work rifling through a Chinese-English dictionary to go through new words with their daughter, even though their own English was hesitant. Their daughter went on to graduate from the University of Maryland and works as an accountant.

"I know for immigrant families, it's very hard for their children," Dai said. "I want our students and our children to be better than us in America. They have very rich potential."

The all-volunteer initiative, which operates through the school year, doesn't receive county funding but does receive support from the school system's ESOL staff. Donations from businesses and individuals and a membership fee of $30 per family pay the program's expenses, which are about $10,000 a year, the bulk of which is for renting the space.

Many of the tutors initially volunteered to fulfill their community service hours for graduation, but the majority have stayed on after completing the requirement.

Karen Shih, 16, said she became more appreciative of the struggles her parents and other immigrants went through. Last summer, she asked her parents to send her to Taiwan so she could improve her Chinese and be a better tutor.

"I just honestly can't imagine having to move all across the world," said Karen, a sophomore at Blake High School in Silver Spring. "English is a strange language to learn. There's a rule, and then they break the rules. There are just so many things you take for granted."

Karen C. Woodson, director of the school system's ESOL office, said she considers the tutoring program a "best practice" because research has shown that peer-to-peer tutoring outside of school helps children learn English more quickly.

"It has a wonderful community involvement," she said.

The tutoring service has expanded to include the parents of the students. About 40 adults have signed up for English classes, and two of their teachers are Chinese American college students.

On a recent Saturday, the cafeteria is filled with the chatter of Chinese and the halting starts of English. Hello Kitty and SpongeBob backpacks hang on chairs.

Some students are working on biology homework. Others are reading picture books. And a few girls are talking about the strange American custom of the homecoming dance.

"It sounds awesome," said Alice Chang, 15, a sophomore at Wootton High School, who immigrated here last year. "We never had it in Taiwan."

Her friend Tiffany Yang, who was her first tutor, shakes her head at the changes in Alice.

Last year, "I tried to talk to her in English, but she didn't want to at first," said Tiffany, a senior at Churchill High School in Potomac. "She only talks in English this year."

Above, Evan Jong, 14, helps Michael Lin, 5, during a Saturday morning tutoring session at Robert Frost Middle School in Rockville. The program pairs Chinese American students with recent immigrants. Across the table are Daniel Xing, 6, and William Leung, 14. At top, Richard Lin, 7. Above right, Brigitta Dai, who helped start the program 14 years ago, offers lighthearted encouragement to Irene Su, 6. "I know for immigrant families, it's very hard for their children," Dai said. "I want our students and our children to be better than us in America. They have very rich potential."Tutoring is also offered to adults. Above from left, Zhi-Ghu Li, Chin-Cheng Li, Chun-Jen Chang and Qi Lan Luo. Below, Jennifer Chu, 14, and Joanna Chen, 8.Betty Leung and tutor Dennis Yo, 14. The program is the county's largest in which students teach others English.Helen Chen, 15, left, and Cindy Chang, 14. The program is funded by donations and a $30 fee per family.