The Balto-Slavic languages form a branch of the Indo-European family of languages, traditionally comprising the Baltic and Slavic languages. Baltic and Slavic languages share several linguistic traits not found in any other Indo-European branch,  which points to a period of common development.
Countries where an East Baltic language is the national language. The Baltic languages belong to the Balto-Slavic branch of the Indo-European language family. Baltic languages are spoken by the Balts, mainly in areas extending east and southeast of the Baltic Sea in Northern Europe.