Language immersion is an educational paradigm with the goal of helping students achieve fluency in a second language by placing them in a pedagogical environment which simulates first language learning. Immersion refers to this environment, where all (or at least most) verbal transactions occur in the target (second language). For example, immersion programmes may teach math and science in the target language, and the earliest conception of an immersive programme was aimed at helping children still within the sensitive period of language acquisition develop bilingual capabilities. Immersion programmes may subscribe to a variety of educational philosophies, including dual-language and two-way immersion. Immersion programmes today are used to enhance multiculturalism, to support the integration of immigrants, but also to protect endangered languages and to help heritage speakers develop and maintain a connection to their cultures. Some language immersion research is beginning to examine cognitive advantages acquired by participants, including protective factors against language deterioration in the aged.