The federal government no longer should focus its efforts to aid non-English-speaking students primarily on bilingual education because there is little evidence those programs work, controversial new Department of Education studies conclude.

The studies, begun in the Carter administration and not yet made public, say that decade-long federal efforts that have cost more than $1 billion and pressured 500 school districts to teach English-deficient children in their own language first, were based on false assumptions. The studies found that some children spoke English better than their native tongue and that poverty and other factors may have had as much to do with poor performance in school as language.

Discretion for which special programs to use should be returned to state and local school officials, and the burden of proving program effectiveness in civil rights enforcement should be shifted from the local to federal government, an overview recommends.

Secretary of Education Terrel H. Bell has yet to review the studies. He has said recently that he doesn't think the federal government should tell local school boards which method to help children learn English. A spokesman said Bell was no longer forcing local school boards to abide by the so-called Lau remedies, regulatory guidelines that had been construed to require bilingual programs.

The findings could have a dramatic impact on bilingual programs and court cases affecting hundreds of thousands of youngsters. Obtained by The Washington Post through a Freedom of Information Act request, they already have been released under subpoena by the state of Texas. The state's attorneys hope to use them in appealing a federal judge's order requiring bilingual programs through the 12th grade.

Hispanic and other groups that have pushed for bilingual programs have attacked the findings as biased. Tracy Gray, of the Center for Applied Linguistics in Washington, contended that the new studies were flawed because project director Alan L. Ginsberg is opposed to bilingual programs.

Roger Rice, a lawyer for Mexican-American parents in the Texas case, said he was more concerned about the study recommendation to return total responsibility to the local level.

"If the feds take a hands-off attitude, then language-limited parents are going to have to match wits themselves with school board statisticians to try to get help for their kids," he said.

The findings also pose a political dilemma for the Reagan administration, which has tried to cultivate the growing Hispanic vote in such large states as California, Texas and New York, where two-thirds of the children needing language help are located.

For instance, Bell junked some proposed bilingual regulations in February as too burdensome and costly, but he saved a program for financing bilingual education from huge cuts by keeping it separate from an education block grant.

The project team began the studies last summer, Ginsberg said, when the Carter administration proposed the bilingual rules that Bell rejected in February.

One study concluded that the number and needs of minority-language children had been misidentified. It estimated that only 1 million children need the language help, not 3.6 million, the figure usually cited by the Department of Education.

A review of previous studies showed little evidence that the emphasis on "transitional bilingual education" programs was justified, Ginsburg and Beatrice F. Birman wrote in the overview. Only 11 of 25 studies reported any positive effects from that method as compared with such approaches as extra or intensive instruction in English, they said.

In addition, the studies showed a shortage of 13,000 bilingual teachers and confirmed estimates that a full program could cost up to $600 million nationwide.

Gary Jones, deputy under secretary of education for planning and budget, said that he recognized that Hispanic leaders would criticize the findings "because they undermine their whole program."

Jones has been a member of the school board in Fairfax County that won a challenge to federal government's reliance on bilingual programs. The county uses an "English as a second language" program of additional instruction rather than teaching in 50 languages represented in the county's enrollment.

"We were able to prove our approach was every bit as effective as theirs," Jones said. He said the department's new studies showed that such decisions should be left to local officials.

Ginsberg said that neither the Carter nor Reagan administration officials had tried to interfere with or shape the study team's conclusions.

The overview noted that department's office of civil rights had negotiated more than 500 compliance agreements with school districts since 1975 to remedy minority students' language deficiencies. With few exceptions, such as that in Fairfax County, the only acceptable remedy was transitional bilingual education, he said.

Similarly, under a separate program to encourage voluntary support by school districts, the federal government has financed only bilingual programs, the report added. graphics: photo. Terrel H. Bell.....yet to review deapartment studies.