There are four main types of dual language programs, which mainly differ in the population:
Developmental, or maintenance, bilingual programs. These enroll primarily students who are native speakers of the partner language.
Two-way (bilingual) immersion programs. These enroll a balance of native English speakers and native speakers of the partner language.
Foreign language immersion, language immersion or one-way immersion. These enroll primarily native English speakers.
Heritage language programs. These mainly enroll students who are dominant in English but whose parents, grandparents, or other ancestors spoke the partner language.