Growing numbers of schools are offering dual-language classes, where teachers split instruction between English and a second language. The numbers of dual-language-immersion programs have been steadily growing in public schools over the past decade or so, rising to more than 2,000 in 2011-12, according to estimates from national experts. That growth has come even as the numbers of transitional-bilingual-education programs shrank in the aftermath of heated, politically charged ballot initiatives pushing English immersion in states like Arizona, Massachusetts, and in California. Experts say the interest in dual-language programs now is driven by an increased demand for bilingual and biliterate workers and by educators who see positive impacts on academic achievement for both English-learners and students already fluent in English.