Children grow up in societies varying on a continuum between monolingualism and multilingualism. Children from Indigenous/Tribal, Minority and Minoritized communities are subjected to the processes of discrimination and stigmatisation of their languages, and glorification of more dominant languages. The processes of development of childhood multilingualism and multilingual socialisation are discussed in the context of multilingual and relatively monolingual societies. Developmental stages and strategies in multilingual socialisation are discussed to show the complexities in the relationship between multilingual orientation of societies and formal educational practices. We discuss how schools as social power instruments perpetuate inequality and discrimination and violate linguistic human rights of children. Social practices and State (and local) policies in education often promote linguistic homogenisation and loss of childhood multilingualism, leading to (linguistic) genocide in education. In conclusion, the chapter reflects on the meaning and implications of growing up in a multilingual world, and how implementation of children’s LHR can develop and maintain/revitalise multilingualism.