Historically in the US, language policies and programs have often been subtractive, but dual language programs are additive, which means that they're focused on developing, cultivating, and sustaining two languages.
Históricamente, las políticas lingüísticas estadounidenses muchas veces han sido sustractivas, pero los programas de lenguaje dual son aditivos, lo cual significa que se enfocan en desarrollar, cultivar y sostener dos idiomas.