Claim: South Slavic languages are unique and distinct from Eastern and Slavic languages due to a period of political unity.
Evidence: Furthermore, Matasović argues, there was never a period of cultural or political unity in which Proto-South-Slavic could have existed during which Common South Slavic innovations could have occurred. Most of these are not exclusive in character, however, and are shared with some languages of the Eastern and Western Slavic language groups (in particular, Central Slovakian dialects).