The research quite clearly shows that the environment in which the person lives and, of course, contact with that language are the principal factors involved in maintaining second-language proficiency. Studies on the first immersion programs have clearly shown that the support and supervision that students are given by their schools and parents and the fact that they live in an environment enabling them to use their second language are enormous factors in enabling them to retain their language skills.
Many young anglophones who left English-language schools and then learned French say they no longer have an opportunity to use the language once they leave the school environment. Many francophones decide to speak English because they feel that no one around them speaks French. This kind of communication may be a problem precisely because no value is necessarily attached to the use of French in that environment. Further research must be conducted in order to gain a clearer understanding of why some individuals who left immersion programs and whose bilingualism levels were very high subsequently managed to maintain those levels.