1) Balto-slavic 2) Balto-slavic language 3) Balto-slavonic 4) Bulgarian or Polish 5) Bulgarian, Czech or Serbian 6) Czech or Polish 7) Czech, polish, and others 8) Czech, Polish, etc 9) East European language 10) European language branch 11) European language family 12) From Serbia or Croatia 13) From Zagreb Found on https://www.crosswordclues.com/clue/slavic