As Grace Lee Chou rang a brass school bell by hand in the hallways of Loch Raven High School on a recent Sunday afternoon, television sets in many area homes were tuned into the Ravens game and families were busy with typical weekend activities.

But six first- and second-graders were soon hard at work in a classroom, repeating letters and consonant blends in unison as their teacher, Julie Liu, pointed to them one by one on a chalkboard.

The children were competing to see who could recite the letters the loudest and who could get the most correct, a scene common in schools the world over.

And, while it may seem like a regular lesson was taking place, the two-semester curriculum being taught is anything but routine. The children are learning Mandarin — one of the world's most difficult languages — at the Chinese Language School of Baltimore.

It was just another two-hour Sunday class for the 30 students ages 5 to 18, who are grouped in five classes by age and skill level at the school, a nonprofit organization in its 43rd year.

Eugenia Henry, chairwoman of the school's board of directors and a former principal, said the school was founded in 1971 by Jacob Huang, who saw a need for American-born Chinese children to be able to converse with relatives in their native tongue.

"We parents can all teach our kids Chinese — or math or chemistry, for that matter — but they don't listen to us," said Henry, 57, who works as a statistical consultant and migrated to the U.S. from Taiwan in 1979. A Sparks resident, she has served in various capacities at the school since 1995.

"My three kids all graduated from the Chinese School and I really appreciated all that the teachers taught them," she said of her grown children. "Some parents who didn't send their children to Chinese school tell me they regret that choice now that their kids are older."

Chou concurred, adding, "If you don't pick up the language early, then it's usually too late."

In addition to their mission of bringing Chinese families closer together through their shared culture and language, administrators want to broaden the outreach of the school by attracting more Americans, Henry said.

While the school has always welcomed non-Chinese students, advertising that educational philosophy has become more of a necessity these days, she said.

The school's enrollment is slowly shrinking as a new trend related to the 2008 downturn in the U.S. economy has been developing, Henry said.

Increasingly, more immigrants who come to America for a college education are, after graduation, returning home to Taiwan, Singapore and Hong Kong to work and start families, she said.

Grace Lee Chou said she came to the United States from Taiwan in 1996 to attend graduate school at Johns Hopkins University and stayed in Baltimore. An executive director of a nonprofit, she and her husband, Harry Chou, who is the school's principal, live in Cockeysville with their son, Isaac, 13, who has taken classes for eight years at the language school.

But that once-typical sequence of life events for immigrants is changing, they say.

"Shrinking enrollment is not unique to our school, but is a general phenomenon occurring at Chinese language schools across the U.S.," Henry said, noting there are 27 similar schools in the Washington-Baltimore area. "It's a question of supply and demand."

The economy in Taiwan is doing well and the nightlife in the main cities there is livelier, with clubs still open at 2 a.m. even on weekdays, Grace Lee Chou said.

Added Henry: "They don't want to suffer the lifestyle here. They say it's too boring."

Grace Lee Chou said the school's leaders are also encountering fewer families from China in the Baltimore metro area.

"As older students graduate [from the Chinese Language School] and receive their certificates, younger students are not enrolling to take their places," she said.