The East, West and South Slavic branches of Indo-European. Belongs here: Russian, Polish, Czech, Slovak, Ukrainian, Belarusian, Bulgarian, Macedonian, Serbian, Croatian, Bosnian, and Old Church Slavonic as the family's earliest written liturgical stage. Does not belong here: a Baltic language; Baltic and Slavic share a documented common ancestor further back but are classified as separate branches per Glottolog, placed in a different subcategory below.