Harmonious bilingual development is the experience of well-being in a language contact situation involving young children and their families. While so far no systematic ethnographic studies of harmonious bilingual development exist, the following constituting elements are proposed: the use of parent–child conversations employing basically a single language, children’s active use of two languages rather than just one, and children’s more or less equal proficiency in each language. The factors contributing to these elements most likely are positive attitudes to early bilingualism, discourse socialization patterns and the frequency with which children hear each language.

While some research investigating these factors has been initiated, a new theory- and practice-oriented research focus on harmonious bilingual development framed within the larger context of well-being research is needed for a deeper understanding of young children and their families’ positive experience with bilingual development and the factors that may foster it.