BOSTON -- Gov. Charlie Baker on Wednesday signed a law giving more flexibility to school districts to offer bilingual education.

"I believe this legislation keeps the best of what we had and makes it possible to create alternatives for people for whom structured immersion hasn't worked," Baker said, speaking to reporters in Boston.

In 2002, voters passed a ballot question requiring school districts to use an English immersion program to teach English to non-native speakers. That means those students learned subjects like science and math in English.

The new law will keep English immersion as an option but will give school districts more flexibility to offer other options, such as bilingual education. The bill gives parents of non-native speakers a greater role in deciding which programs a school will offer. It also creates a "seal of biliteracy," so students who are fluent in two languages get a credential they can show colleges or prospective employers.

Baker said his concern about the bill had been that data shows structured immersion worked for tens of thousands of children. "My concern was that we would throw the baby out with the bathwater," Baker said.

The bill does not do that, he said. "I believe the legislation makes it possible for the kids who benefit from structured immersion to continue to benefit from that, but it also gives communities the opportunity to put together evidence-based alternatives that they believe can work for other kids for whom structured immersion doesn't work," Baker said.

Baker stressed that the bill has a mechanism to continually evaluate what is working for a school district.

"It's really important for everybody that kids who come here who are not proficient in writing or reading or speaking English become proficient, because it's a fundamental building block of success," Baker said.

Advocates for overturning the current law say English immersion works for some students, but not others. They note that students enter schools at different ages with different educational and linguistic backgrounds.

The bill would have the biggest impact in urban areas -- places like Boston, Springfield, Worcester and Lawrence -- that have huge concentrations of students speaking other languages. It would also affect Gateway Cities, which are often struggling cities with the potential to anchor regional economies -- places like Holyoke, New Bedford and Chelsea.

"Every student has unique needs, and it is our obligation to foster an environment where they are afforded an education tailored to them," House Speaker Robert DeLeo, D-Winthrop, said in a statement.

Senate President Stan Rosenberg, D-Amherst, said in a statement, "Allowing parents and local school districts the flexibility to choose the most effective programs to cater to the specific needs of their students is not only good public policy but also what is best for our students to be successful."