Children can only learn to speak if supportive adults interact with them. Parents who speak a "language of the heart" that is different from the environmental language usually want their children to speak their language. Many children, however, do not speak their parents' language, or do not speak it well. This does not contribute to families' well-being and their harmonious bilingualism. Making sure that children learn to speak their parents' language requires extra "work" and effort from parents in a bilingual setting. It is through speaking a lot with children and engaging in many language based activities that parents can support their children's language development. In addition, parents must create the need for children to speak the language parents speak to them. All this is part of Family Language Policy. This talk explains how adaptive and stimulating oral interaction between parents and their young children can help build the basis for successful language transmission and harmonious bilingualism.