In the United States, the term bilingual education generally refers to programs that provide support to students with limited English proficiency. Some of these programs teach academic subjects in the students' home language (usually Spanish) while also requiring language-minority students to take classes in English as a second language (ESL). Other programs aim to teach English to language-minority students by immersing them in English-only classes. Still others are two-way, or dual-language, programs that aim for fluency in two languages—for example, such a program might simultaneously teach Spanish to English-speaking students and English to Spanish-speaking students. These major approaches have several variations, and districts and schools may use a combination of them.

Thus, when people argue over bilingual education's effectiveness or ineffectiveness, they could be discussing different forms of bilingual education. In public debate, however, bilingual education usually refers to transitional bilingual education (TBE), which provides native-language instruction...