In its interdisciplinary orientation, the book is aimed at all professional groups who interact and communicate with children in early and primary education, as well as parents and other interested parties. In keeping with the character of a compact textbook, the following main topics are discussed: linguistic diversity in an immigration context, growing up in several languages with case studies, bilingual and biliteral language acquisition, milestones and disorders in language development, language diagnostics, models of multilingual education and school development, language education, and day-to-day integrated support in day care, crèche, day care centre, and primary school.