Slavic languages different from Church Slavonic
Czech–Slovak
Czech
Slovak
Lechitic
Polabian
Polish
Pomeranian
Kashubian
Silesian (often seen as a dialect of Polish)
Sorbian
Lower Sorbian
Upper SorbianSome linguists speculate that a North Slavic branch has existed as well. The Old Novgorod dialect may have reflected some idiosyncrasies of this group.
Mutual intelligibility also plays a role in determining the West, East, and South branches. Speakers of languages within the same branch will in most cases be able to understand each other at least partially, but they are generally unable to across branches (which would be comparable to a native English speaker trying to understand any other Germanic languages besides Scots).
The most obvious differences between the East, South, and West Slavic branches are in the orthography of the standard languages: West Slavic languages (and Western South Slavic languages – Croatian and Slovene) are written in the Latin script, and have had more Western European influence due to their proximity and speakers being historically Roman Catholic, whereas the East Slavic and Eastern South Slavic languages are written in Cyrillic and, with Eastern Orthodox or Uniate faith, have had more Greek influence. Two Slavic languages, Belarusian and Serbian, are biscriptal, commonly written in either alphabet. East Slavic languages such as Russian have, however, during and after Peter the Great's Europeanization campaign, absorbed many words of Latin, French, German, and Italian origin.
The tripartite division of the Slavic languages does not take into account the spoken dialects of each language. Of these, certain so-called transitional dialects and hybrid dialects often bridge the gaps between different languages, showing similarities that do not stand out when comparing Slavic literary (i.e. standard) languages. For example, Slovak (West Slavic) and Ukrainian (East Slavic) are bridged by the Rusyn language/dialect of Eastern Slovakia and Western Ukraine. Similarly, the Croatian Kajkavian dialect is more similar to Slovene than to the standard Croatian language.
Although the Slavic languages diverged from a common proto-language later than any other groups of the Indo-European language family, enough differences exist between the various Slavic dialects and languages to make communication between speakers of different Slavic languages difficult. Within the individual Slavic languages, dialects may vary to a lesser degree, as those of Russian, or to a much greater degree, like those of Slovene.Church Slavonic language, variations of Old Church Slavonic with significant replacement of the original vocabulary by forms from the Old East Slavic and other regional forms. The Bulgarian Orthodox Church, Russian Orthodox Church, Polish Orthodox Church, Macedonian Orthodox Church, Serbian Orthodox Church, and even some Roman Catholic Churches in Croatia continue to use Church Slavonic as a liturgical language. While not used in modern times, the text of a Church Slavonic Roman Rite Mass survives in Croatia and the Czech Republic, which is best known through Janáček's musical setting of it (the Glagolitic Mass).
Interslavic language, a modernized and simplified form of Old Church Slavonic, largely based on material that the modern Slavic languages have in common. Its purpose is to facilitate communication between representatives of different Slavic nations and to allow people who do not know any Slavic language to communicate with Slavs. Because Old Church Slavonic had become too archaic and complex for everyday communication, Pan-Slavic language projects have been created from the 17th century onwards in order to provide the Slavs with a common literary language. Interslavic in its current form was standardized in 2011 after the merger of several older projects.