The Slavic subfamily has three divisions: East Slavic, West Slavic, and South Slavic. Members of the East Slavic branch are Russian, or Great Russian; Ukrainian, also called Little Russian or Ruthenian; and Belarusian, or White Russian. Together they claim close to 225 million native speakers, almost all in Russia, Ukraine, Belarus, and neighboring countries. The West Slavic branch includes Polish, Czech, Slovak, Lusatian, Kashubian, and the extinct Polabian. The living West Slavic languages can claim approximately 56 million speakers, chiefly in Poland, the Czech Republic, and Slovakia. The South Slavic tongues consist of Serbo-Croatian, Bulgarian, Slovenian, and Macedonian, together with the liturgical language known as Church Slavonic. The first four are native to more than 30 million people, largely in Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, Macedonia, and Bulgaria.
All Slavic tongues are believed to have evolved from a single parent language, usually called Proto-Slavic, which, in turn, is thought to have split off much earlier (possibly c.2000 B.C.) from Proto-Indo-European, the original ancestor of the members of the Indo-European language family. Proto-Slavic was probably still common to all Slavs in the 1st cent. B.C., and possibly as late as the 8th or 9th cent. A.D., but by the 10th cent. A.D. the individual Slavic languages had begun to emerge.