How important is it that the child's two languages are practiced and supported outside the home?

          Where families are in-migrants, guest workers or refugees, there may be little support for the home language in the community or in formal schooling. When such parents feel isolated, there is sometimes the tendency to feel like giving up the heritage language and speaking the regional majority language to the child. The pressure in the community tends to be to speak in the language of the region rather than a foreign language. The answer is that bilingualism inside the child can be effectively sustained through the language of the home being different from the language of the community. However, this will be a challenge and a constant journey that moves across bright mountain tops and dark valleys. If the child learns the community language via the school and the street, there is sufficient support for that language outside the home for the child to become fully bilingual. The problem is not usually with learning the majority language of the region, but in maintaining the language of the home. Their language being an island in the home should not deter determined parents.

SOURCE : A PARENTS' AND TEACHERS' GUIDE TO BILINGUALISM