Domestic and International Common Language (DICL) Database

The database contains 11 index measures of linguistic similarity between 242 countries, both domestically and internationally. The domestic measures capture linguistic similarities present among populations within a single country while the international indexes capture language similarities between two different countries. The indexes, which are based on 6,674 languages, reflect three different dimensions of language: common official languages, common native and acquired spoken languages, and linguistic proximity across different languages. This database has many uses, such as in the study of bilateral flows—including FDI, migration, and international trade—as well as in regional or country level analyses. Version history: Version 2 (Dec. 2024): Version 2 of the Dataset added three additional indices (BPN, BPA, and BPS). It also corrected an issue with the calculation of the linguistic proximity indices in version 1; a small number of languages that terminated at the same point on a linguistic tree were unintentionally treated as being the same language and were omitted from the LPN, LPA, and LPS calculations. This omission affected relatively few indices overall and very few indices significantly. However, a small number of linguistic proximity indices are substantially larger after the correction. Finally, version 2 also reintroduced one language that had been inadvertently omitted in version 1, resulting in a small change to the index values for several countries, primarily in East and Southeast Asia. Version 1 (Mar. 2024): Initial release on Dataverse.