This book is a multidisciplinary analysis of the meaning and dynamics of multilingualism from the perspectives of multilingual societies and language communities in the margins, who are trapped in a vicious circle of disadvantage. It analyses the social, psychological and sociolinguistic processes of linguistic dominance and hierarchical relationships among languages, discrimination, marginalisation and assertive maintenance in multilingualism characterised by a Double Divide, and shows the relationship between educational neglect of languages, capability deprivation and poverty, and loss of linguistic diversity. Its comparative analysis of language-in-education policies and practices and applications of multilingual education (MLE) in diverse contexts shows some promises and challenges in the education of indigenous/tribal/minority children. This book will be of interest to students, researchers, educators and practitioners in sociolinguistics, educational linguistics, psycholinguistics, multilingualism and bilingual/multilingual education.