First Lady Rosalynn Carter and Secretary of Education Shirley Hufstedler sat through a fourth grade geography lesson on Mexico, listened to a poem on slavery recited in Spanish and viewed a presentation on Latin American music and dance yesterday at Washington's Oyster Elementary School to mark the opening of the new Department of Education.

Speaking to the school's 235 students in both Spanish and English the first lady and Hufstedler stressed the importance of bilingual education. Oyster is the only school in the city in which students are taught in both English and Spanish in all subjects.

Shyly telling the students -- many of whom wore Latin American peasant dresses, sombreros and bandanas -- that "you'll have to correct my Spanish," Mrs. Carter told the youths she regretted not having had the chance to attend a school like Oyster when she was young.

She added in Spanish that she began learning that language after she came to Washington.

Later, Carter viewed student exhibits of puppets, sculpted insects, dyed cloth and clay artworks, stopping from time to time to say "very nice," or ask the children to tell her their grade, or to place her arm around a student and pose as the child's mother snapped a picture.

"I think she'd be a good teacher. She's nice to children. I think she likes children," said Claudina Gomez, 9, a fourth grader who, dressed in her floor-length white peasant dress, got to sit next to the first lady.

The Oyster bilingual program began in 1973 mainly to serve the large Spanish-speaking population that was then beginning to settle in the Adams-Morgan section of the city, according to Marcelo Fernandez, director of bilingual education.

Over the years, the program grew more popular with American-born residents of the area interested in giving their children a totally bilingual bicultural education.