Mother languages, along with linguistic diversity, matter for the identity of individuals. As sources of creativity and vehicles for cultural expression, they are also important for the health of societies. Not least, languages are factors for development and growth. We know how important education in the mother language is for learning outcomes. Mother language instruction is a powerful way to fight discrimination and reach out to marginalized population. As wellsprings of knowledge, languages are also starting points for greater sustainability in development, for managing more harmoniously our relationship with the environment and change.