This book draws on case studies of language management within British organisations to examine the decisions they make about language diversity in their professional communications in order to be successful in a multilingual world. It explores the practices that the organisations use to manage language diversity in interorganisational relationships, and why certain practices occur in some situations and not others. The book highlights how organisations rely on individual employees to perform a variety of language tasks and the implications of this; the effect of English as a global lingua franca; and the translation challenges which organisations face. The book demonstrates that practices to manage language diversity are often a result of the resources organisations have at given moments in time, rather than being part of a deliberate language management strategy.