Plurilingual communication is common practice in most urban areas. Societal domains such as business and science nowadays see themselves as international, and plurilingual communication is the rule rather than the exception. But how do other players in critical domains of modern societies, and more specifically, in education react to this situation? This volume of the Hamburg Studies in Linguistic Diversity (HSLD) series explores this question along three major lines. One group of contributions sheds light on educational policies in Europe and beyond. A second group of contributions elucidates what interaction and communication practices develop in multilingual contexts. The focus is on school settings. Thirdly, we present articles that discuss the effects of plurilingual settings and plurilingual practices on language development. As a whole this volume shows how linguistic diversity shapes a central domain of our societies, namely education, and how it also impacts upon the development of the individuals interacting in this domain.