Slavic standard languages which are official in at least one country: Belarusian, Bosnian, Bulgarian, Croatian, Czech, Macedonian, Montenegrin, Polish, Russian, Serbian, Slovak, Slovene, and Ukrainian. The alphabet depends on what religion is usual for the respective Slavic ethnic groups. The Orthodox use the Cyrillic alphabet and the Roman Catholics use Latin alphabet, the Bosniaks who are Muslims also use the Latin. Few Greek Roman and Roman Catholics use the Cyrillic alphabet however. The Serbian language and Montenegrin language uses both Cyrillic and Latin alphabets. There is also a Latin script to write in Belarusian, called the Lacinka alphabet.
What determined what alphabet people used?
religion