Built around the concept of linguistic and cultural plurality, this book defines language as an instrument of action and symbolic power. Plurality is conceived here as : a complex array of voices, perspectives and approaches that seeks to preserve the complexity of the multilingual and multicultural enterprise, including language learning and teaching ; a coherent system of relationships among various languages, research traditions and research sites that informs qualitative methods of inquiry into multilingualism and its uses in everyday life ; a view of language as structured sociohistorical object, observable from several simultaneous spatiotemporal standpoints, such as that of daily interactions or that which sustains the symbolic power of institutions. This book is addressed to teacher trainers, young researchers, decision makers, teachers concerned with the role of languages in the evolution of societies and educational systems. It aims to elicit discussion by articulating practices, field observations and analyses based on a multidisciplinary conceptual framework.