This paper provides an introduction and overview of my research on the Economics of Language. The approach is that language skills among immigrants and native-born linguistic minorities are a form of human capital. There are costs and benefits associated with this characteristic embodied in the person. The analysis focuses on the economic and demographic determinants of destination language proficiency among immigrants. This is based on Exposure, Efficiency and Economic Incentives (the three E’s) for proficiency. It also focuses on the labor market consequences (earnings) of proficiency for immigrants and native-born bilinguals. The empirical testing for the US, Canada, Australia, Israel and Bolivia is supportive of the theoretical models.