Typical bilingual instruction is presented with the goal of acclimating ELL students to English. Bilingual classrooms consist of a group of students who are all unfamiliar with English, and students may be in bilingual programs for many years, separated from their peers of different backgrounds and abilities.
Two-way immersion (or TWI) is presented as an alternative to bilingual instruction. Unlike bilingual classrooms, a TWI classroom has both ELLs, and students who are fluent in English. Instruction takes place in both languages (the home language of the ELLs, and English), so both students are learning a new language.
Diversity is a large issue in public education – even in New York City, schools can become separated by race. Establishing a TWI program encourages more upper-middle class students to enroll in more diverse schools.