Language difference and regional authority

This paper draws on research in geography, linguistics, and political science to explain the incidence of language regions and their effect on regional authority. It conjectures a chain of mechanisms beginning with the physical and political barriers to human interaction and culminating with contemporary patterns of regional authority. Using data on 1767 regions in 95 countries, it finds causal power in the claim that the linguistic distinctiveness of a region reflects the ratio of internal interaction to external interaction. Finally, the effects of a language region for regional authority depend decisively on the openness of the political regime