This book proposes a path-breaking study of the economics of multilingualism at work, proposing a systematic approach to the identification and measurement of the ways in which language skills and economic performance are related. Using the instruments of economic investigation, but also explicitly relating the analysis to the approaches to multilingualism at work developed in the language sciences, this interdisciplinary book proposes a systematic, step-by-step exploration of the issue. Starting from a general identification of the linkages between multilingualism and processes of value creation, it reviews the contributions of linguistics and economics before developing a new economic model of production in which language is taken into account. Testing of the model using data from two countries provides quantitative estimations of the influence of multilingualism on economic processes, showing that foreign language skills can make a considerable contribution to a country's GDP. These findings have significant implications for language policy and suggest strategies helping language planners to harness market forces for increased effectiveness.