The Origins of Ethnolinguistic Diversity†

Ethnicity has been widely viewed in the realm of social sciences as instrumen-tal for the understanding of socioeconomic processes. Within economics, there has been a large and growing literature, beginning with Mauro (1995), that uses indexes of ethnolinguistic diversity either as an instrument or as an explanatory variable for various economic indicators (e.g., Easterly and Levine 1997; Alesina et al. 2003; and Banerjee and Somanathan 2007, among others). Similarly, within sociology, anthropology, political science, psychology, and history, the volume of work inves-tigating the causes and effects of ethnicity attests to its paramount importance.1 The goal of this study is to empirically uncover the common exogenous features that produce the observed diversity at a global scale. It does so by bringing into the foreground the role of geographic heterogeneity in separating populations leading to the formation of distinct linguistic groups. The empirical investigation, conducted at various levels of spatial aggregation, establishes that geographic variability, captured by variation in regional land quality and elevation, is a fundamental determinant o