Slavs
Standardised Slavic languages that have official status in at least one country are: Belarusian, Bosnian, Bulgarian, Croatian, Czech, Macedonian, Montenegrin, Polish, Russian, Serbian, Slovak, Slovene, and Ukrainian.
Serbs
Serbian is an official language in Serbia and Bosnia-Herzegovina and is a recognized minority language in Montenegro (although spoken by a plurality of population), Croatia, Macedonia, Romania, Hungary, Czech Republic and Slovakia. Older forms of literary Serbian are Church Slavonic of the Serbian recension, which is still used for ecclesiastical purposes, and Slavonic-Serbian—a mixture of Serbian, Church Slavonic and Russian used from mid-18th century to the first decades of the 19th century.