Proto-Balto-Slavic language

Proto-Balto-Slavic (PBS or PBSl) is a reconstructed proto-language descending from Proto-Indo-European (PIE). From Proto-Balto-Slavic, the later Balto-Slavic languages are thought to have developed, composed of the Baltic and Slavic sub-branches, and including modern Latvian, Lithuanian, Polish, Russian and Serbo-Croatian, among others.