Washington-area school officials predicted recently that the Reagan administration's decision to scrap proposed bilingual education regulations would have minimal immediate impact on existing bilingual courses, but some expressed fears that the decision could signal the gradual unraveling of those programs.

The proposed regulations, which were scheduled to go into effect in June, would have forced 500 large school systems in the nation -- including Fairfax County and the District of Columbia -- to offer non-English speaking students courses in their native language or lose all federal funding for education, which most school systems need to oeprate.

Fairfax County and Prince George's Count officials, who bitterly opposed the proposed federal regulations were jubilant.

"Hallelujah, hallelujah," sang Esther Eisenhower, director of Fairfax's English as a Second Language program, considered a model program in the nation for intensive English-language instruction. "We worked very hard for this."

"I'm not totally against bilingual education," Eisenhower said. Summing up the feelings of many local school officials, Eisenhower said, "What I deplore is the federal government mandating the program." She added that Fairfax, on its own, had fashioned a program tailor-made for its students' needs.

Hispanic leaders in the District of Columbia, united in their support of the bilingual regulations, spent the day meeting to decide how best to fight the Reagan administration's decision. Angel Irene, director of the Council of Hispanic Agencies, said his organization had drafted a letter of protest to the education department.

Roland Roebuck of the D.C. Office of Latino Affairs said that agency has scheduled a forum on the issue for next Tuesday afternoon with members of Congress as well as national and local Hispanic leaders, for whom bilingual education is a rare, uniting political force.

"I see this [decision] as a total disregard of understanding for other people's cultures," Roebuck said. He noted that bilingual education also means that youngsters would study their native culture as well as their native tongue.

Under bilingual education, non-English-speaking students are taught classroom subjects in their native language while receiving instruction in English. Proponents of bilingualism have argued that students fall behind in their subjects when they have to learn English first. Most area schools, however, favor immersing these students in special English courses -- the English as a second language approach, which some consider an alternative to bilingualism.

School officials in Arlington, where foreign students are taught with a combination of bilingual and intensive-English techniques, said the withdrawal of bilingual requirements would not affect their program, but might trigger the end of programs for non-English-speaking students elsewhere. m

"Maybe you won't see it immediately, but go back in two years and you will find school systems doing less and spending less on education for their non-English-speaking students," said Ronald Saunders, Arlington's director of Bilingual Education Projects.

Betty Knight, director of the English for Speakers of Other Languages program in Montgomery County, said she is concerned that because of the new administration's oppostion to bilingualism, Montgomery County might lose some of the $133,000 in federal aid it gets for its bilingual program, serving 250 students. Most of the county's 3,000 foreign-born students are enrolled in special English classes.

District of Columbia officials said there would be no effect on its nine-year-old, Spanish-English bilingual program at Oyster Elementery School in Northwest because the city, not the federal government, provides the $209,000 a year to run the program.

Maria Tukeva, principal of the city's only bilingual career-development program at the Marie Reed Learning Center in Adams-Morgan, also said she is confident her program will continue to get its annual funding of $100,000 from the U.S. Labor Department.