Variations and effects of bilingual education in schools

Bilingual education, on the one hand, means foreign or second language learning and, on the other hand, it means learning processes in a foreign or second language. As a medium of the learning processes or as the language of instruction the majority language and another language are used. In this review, in addition to conventional foreign language learning programs, we present the most important types of bilingual education: content and language integrated learning (CLIL), one-way immersion, and two-way immersion. Additionally, we discuss language programs for heritage language learners, which use their first language as medium of instruction. The research on the effects of these forms of bilingual education on language competencies, proficiency in the non-language subjects, and on non-cognitive variables is summarized for two types of students: those whose first language is the common language and those whose students whose first language is not the common language, taking into account new meta-analytical findings.