Extreme cases.

This study investigates the impact of a minority language on international trade. Using the distance to Hunchun as an instrumental variable, and transaction-level customs data from 2000 to 2015, we investigate the causal impact of common Korean language on international trade between Chinese counties and South/North Korea. The results suggest that a 1% increase in the proportion of population speaking Korean will increase value share and transactions share in trade by 1.8% and 2.3%, respectively. These effects are more pronounced in trade with North Korea and in higher trade share regions. Furthermore, we show that the common Korean language exerts its influence through reducing communication barrier. The impact is mainly observed at the extensive margin rather than the intensive margin. These findings highlight the potential of leveraging minority languages to boost bilateral trade in developing countries.