Slavs
Slavs can be further grouped by religion. Orthodox Christianity is practiced by the majority of Slavs. The Orthodox Slavs include the Belarusians, Bulgarians, Macedonians, Montenegrins, Russians, Serbs, and Ukrainians and are defined by Orthodox customs and Cyrillic script as well as their cultural connection to the Byzantine Empire (Serbs also use Latin script on equal terms). Their second most common religion is Roman Catholicism. The Catholic Slavs include Croats, Czechs, Kashubs, Moravians, Poles, Silesians, Slovaks, Slovenes, and Sorbs and are defined by their Latinate influence and heritage and connection to Western Europe. There are also substantial Protestant and Lutheran minorities especially amongst the West Slavs, such as the historical Bohemian (Czech) Hussites.
Ukraine
According to the constitution, the state language of Ukraine is Ukrainian. Russian is widely spoken, especially in eastern and southern Ukraine. According to the 2001 census, 67.5 percent of the population declared Ukrainian as their native language and 29.6 percent declared Russian. Most native Ukrainian speakers know Russian as a second language. Russian was the "de facto" official language of the Soviet Union but both Russian and Ukrainian were official languages in the Soviet Union and in the schools of the Ukrainian SSR learning Ukrainian was mandatory. Effective in August 2012, a new law on regional languages entitles any local language spoken by at least a 10 percent minority be declared official within that area. Russian was within weeks declared as a regional language in several southern and eastern oblasts (provinces) and cities. Russian can now be used in these cities'/oblasts' administrative office work and documents. On 23 February 2014, following the 2014 Ukrainian revolution, the Ukrainian Parliament voted to repeal the law on regional languages, making Ukrainian the sole state language at all levels; however, the repeal was not signed by acting President Turchynov and current President Poroshenko.