An effort to improve bilingual education — a longstanding challenge for the city’s public schools — was dealt a blow this weekend when allegations surfaced that some bilingual teachers from the Dominican Republic were being forced to hand over most of their paychecks to cover inflated rents charged by their bosses.

Nathaniel Styer, a spokesperson for the Department of Education, called the allegations, first reported by CBS2, “disturbing.” He said officials referred the issue to law enforcement to investigate, reassigned the principal, and are offering support to the affected employees.

The educators from the Dominican Republic were part of a “cultural exchange” that Schools Chancellor David Banks announced with fanfare just two months ago, placing 25 bilingual teachers in city schools, through a partnership with the Association of Dominican American Supervisors and Administrators (ADASA-NY) and the Dominican consulate.

“We remain focused on recruiting bilingual educators who speak the languages of our students,” Styer added.

But finding and hiring bilingual educators to serve the city’s tremendously diverse students is a challenge that has bedeviled officials for decades.

Experts said that children who are learning English are most likely to gain competency in all subjects when taught at least partially in their home language – and risk falling behind when they are taught solely in English.

At the time of the announcement, Banks said the program with the Dominican Republic could serve as a model to meet the needs of asylum seeking students and other multilingual learners, and acknowledged the lack of bilingual teachers in the city’s schools.

“For at least 20 years there has been a real shortage of bilingual teachers,” said Mark Cannizzaro, president of the principals’ union, the Council of School Supervisors and Administrators. “And it’s an even bigger problem now.”

Thousands of new students have arrived in city schools over the past few months, largely children of asylum seekers from South and Central America. Some have landed at schools with robust bilingual programs, where they can learn academic content while gaining English skills. Others find themselves lost in classes where the only language spoken is English.

“What we need to see from the Department of Education is a massive investment in bilingual education,” said Council member Shekar Krishnan. “This is the time for the city to make those investments.”

According to education department statistics, approximately 147,000 students in the city’s public schools are considered English Language Learners (ELLs), meaning they have not yet tested proficient in English and require additional support.

But, according to the United Federation of Teachers, fewer than 3,000 teachers are certified as bilingual instructors. That’s approximately one educator for 47 students, although these educators are not evenly distributed throughout the school system. There are also 3,455 educators certified to teach English as a New Language (ENL) but they are not necessarily bilingual themselves, and their classes are primarily in English, according to the UFT. Other teachers may be bilingual, but are not certified.

The vast majority of children in city schools who are categorized as “English Language Learners” receive support through English as a New Language (ENL) classes, which are either standalone classes for students or periods of the day when students are pulled out of their main classes for English instruction.

A smaller portion of schools offer bilingual classes or programs, which either alternate between a student’s home language and English, or transition from the home language to English over time.

Kate Menken, professor of Linguistics at Queens College at the City University of New York, said research shows that bilingual programs are more effective than supporting children solely through ENL. But less than 17% of English Language Learners in the city’s public schools are enrolled in bilingual programs.

“In bilingual education, students can comprehend grade level content while they’re learning the language,” she said. “The research is extremely strong at this point. If you want a child to learn English and to learn academic content better, it’s best to use their home language.”

Menken said the city should invest in more bilingual programming. Other advocates are calling on officials to offer higher pay to teachers who get certified, and to increase funding for schools serving substantial numbers of English Language Learners. They said schools are also in desperate need of bilingual special education teachers and bilingual social workers.

Lupe Hernandez, a member of the Community Education Council for District 2, said that bilingual support for students varies widely: at one school in her district, new students are relying on classmates to translate. At another, the administration and a group of parents scrambled to create a new bilingual classroom days into the new school year.

“They hired a new teacher, and they got that funding through the DOE,” Hernandez said. “I’m just in awe and amazed how much that school was able to pull together.”

Naveed Hasan, a parent at PS 145 on the Upper West Side, hopes his school can serve as a model for others.

The school has taken in both Ukrainian refugees and Spanish-speaking asylum seekers in recent months. He said the school was a natural choice for the children because it already offered bilingual classrooms in each grade for students who speak Russian and Spanish respectively.

“Our principal said send them over, because we have practice doing this work,” Hasan said.

Correction: A previous version of this article misspelled Naveed Hasan's last name.