IF BOSTON schools can’t make faster progress in helping students with limited English skills, the US Department of Education will have good cause to withhold some federal aid. Latino and immigrant groups are asking the department to place conditions on money from the federal Race to the Top grant program requiring that Boston schools make aggressive efforts to educate so-called English language learners. The system’s halting record justifies this tough stance.

Students with limited English proficiency, who make up almost one-fifth the Boston Public Schools’ enrollment, drop out at high rates and score poorly on MCAS tests. The city deserves part of the blame. Until recently, the system did not properly test students whose first language is not English, and it failed to make their parents aware of all the services that might help their children.

Boston and other school districts must do a better job with so-called English language learners because they make up the fastest-growing population group in the schools. Immigrant students’ literacy skills in English often lag behind their ability to speak the language. Yet for years, the city was testing whether incoming students could speak and understand spoken English but not whether they could read or write it. This - and a failure to make clear to parents that their children are entitled to specialized English-as-a-second-language instruction - landed many students in inappropriate classes and contributed to high dropout rates and low test scores.

Superintendent Carol Johnson says she is committed to rectifying past mistakes. In an interview last week, Johnson said the city is doing a better job of testing incoming students, having set up a newcomers’ academy for older students with limited English, hired more teachers of English as a second language, and trained more than 700 regular classroom teachers in the special techniques they would need to make their instruction understandable to English learners.

Latino and immigrant groups also want the city to identify and help those English learners who have stumbled in school because they did not get English-as-a-second-language assistance when they first joined the district. Johnson is open to this demand. “We recognize we’ll have to provide compensatory services to them,’’ she said.

Yet these commitments, while welcome, are overdue. To make sure the city sticks by them, US Secretary of Education Arne Duncan should condition any Race to the Top grants to Boston on their fulfillment.