Language immersion, or simply immersion, is a method of teaching a second language in which the learners’ second language (L2) is the medium of classroom instruction. Through this method, learners study school subjects, such as math, science, and social studies, in their L2. The main purpose of this method is to foster bilingualism, in other words, to develop learners’ communicative competence or language proficiency in their L2 in addition to their first or native language (L1). Additional goals are the cognitive advantages to bilingualism. Immersion programs vary from one country or region to another because of language conflict, historical antecedents, language policy or public opinion. Moreover, immersion programs take on different formats based on: class time spent in L2, participation by native speaking (L1) students, learner age, school subjects taught in L2, and even the L2 itself as an additional and separate subject.