Zusammenfassung:
Countries are not perfectly integrated market areas. Even if institutional differences are much smaller within than between countries, there are persistent local cultural differences. These differences act as barriers that reduce economic exchange: bilateral migration, trade, and knowledge diffusion flows are smaller, and individuals discriminate against unfamiliar dialects. They also act as natural limits to the degree of integration of a labor market, and they cannot (and perhaps should not) be easily affected by policy. Local dialects, shaped over centuries, provide a unique opportunity to measure these barriers.