DINUBA (AP) — A group of teachers, parents and students sued a small Central Valley school district Wednesday, alleging its program to teach English to young elementary school children is ineffective and violates the students' constitutional rights.

Three chapters of the American Civil Liberties Union in California and other civil rights organizations filed the lawsuit against Dinuba Unified School District in Sacramento County Superior Court.

The lawsuit charges that Dinuba Unified uses a grammar-intense curriculum that is unproven for first- and second-grade children and is causing them to fall far behind in both English learning and in other academic skills. During the first half-year they are enrolled in the program, students are taken out of the regular reading curriculum.

That is a violation of the children's right to a fair and equal education under the California constitution, the suit said.

In a written statement, district Superintendent Jose Hernandez said the district could not comment on the allegations or legal arguments in the suit. But, he said, the district and the parties to the lawsuit had a "productive conversation" today.

"The parties have agreed to work together in good faith to avoid costly and excessive litigation," the statement said. "We always want to work with anyone concerned about how we can provide the best education possible for our children."

In a statement on a district website, Hernandez states the program is a high priority for the district to improve students' English proficiency.

More than half the students in the 5,700-pupil district, located in an agricultural community south of Fresno, are English learners.

According to the suit, the method known as Second Language Acquisition Development Instruction calls for 6-, 7- and 8-year-old students to deconstruct sentences and memorize formal parts of speech before they have even acquired basic reading skills or understand such concepts in their native language. The district adopted the method three years ago.

Teachers have repeatedly complained to administrators that this method is inappropriate for young children, said Nona Rhea, a third-grade teacher who is one of four teacher plaintiffs in the suit.

"Day after day, when every minute counts, these kids are memorizing parts of speech, what a modal verb is, or diagraming sentences, when they should have been in the classroom with their peers learning how to read," said Rhea, who taught the method to first- and third-graders. "It's just been frustrating to see this experiment on these kids that has dire results."

Children suffer in their scores and even their attitudes, Rhea said.

"We don't see that much improvement," she said. "We might see the children able to repeat by rote back to us, but we see no correlation in improved reading."

Teachers are not allowed to have students read books, and instead use flashcards to teach which words are prepositions, nouns and verbs, said Mark Rosenbaum, chief counsel for the ACLU of Southern California.

During the second half of the school year, students are moved into the regular reading curriculum, but are lost because they have had no reading instruction, the suit said. Students also have little opportunity to mingle with English speakers, according to the suit.

Last month, teachers voted formally to oppose the program. "I see the lawsuit as a last resort," Rhea said.

Rosenbaum said he does not know of any other district using the method, which Dinuba Unified cleared with the state Department of Education, also named as a defendant.

A department spokesperson said officials are still reviewing the allegations raised in the suit and could not comment.

"It is unfortunate that the parties chose to file suit rather than making a good-faith effort to meet with state officials to address their concerns," officials said in a written statement. "The Department is working hard to help districts meet the needs of English learners."

Since Dinuba implemented the method, the district's progress in English proficiency levels has dropped, the lawsuit said. In 2009, four out of five elementary schools met state English proficiency progress goals. Only one school made the goal last year.

The suit aims to force the district to replace the program with a proven, pedagogical method.

The lawsuit reflects the latest move in a growing wave of criticism leveled against English-language instruction in California schools, which house the highest number of English learners in the nation — 1.6 million students who are mostly Spanish speakers.

Only 11 percent of them achieved proficiency levels in English in the last school year. About a third drop out of school. Only 13 percent go on to college.

Last fall, the U.S. Department of Education found that California's largest school district, Los Angeles Unified, was violating students' rights by failing to provide an adequate English program.

LAUSD is now overhauling its English learner curriculum, the largest in the country with some 200,000 students.

State legislators have also earmarked English learning with several bills designed to improve the quality of instruction. The state Senate on Tuesday approved a bill that would reform the system schools use to move English learners into regular classes.

"Our current system of education English learners is too often an afterthought," said state Sen. Alex Padilla, D-Pacoima.