These include:[4] This is illustrated in the following table: Several isoglosses have been identified which are thought to represent exclusive common innovations in the South Slavic language group.

Furthermore, Matasović argues, there was never a period of cultural or political unity in which Proto-South-Slavic could have existed during which Common South Slavic innovations could have occurred.

Several South-Slavic-only lexical and morphological patterns which have been proposed have been postulated to represent common Slavic archaisms, or are shared with some Slovakian or Ukrainian dialects.

[citation needed] On the other hand, the breakup of the Ottoman and Austro-Hungarian Empires, followed by formation of nation-states in the 19th and 20th centuries, led to the development and codification of standard languages.

The dialects that form the eastern group of South Slavic, spoken mostly in Bulgaria and Macedonia and adjacent areas in neighbouring countries (such as the Bessarabian Bulgarians in Ukraine), share a number of characteristics that set them apart from other Slavic languages:[11][12] Bulgarian and Macedonian share some of their unusual characteristics with other languages in the Balkans, notably Greek and Albanian (see Balkan sprachbund).

Torlakian is thought to fit together with Bulgarian and Macedonian into the Balkan sprachbund, an area of linguistic convergence caused by long-term contact rather than genetic relation.

The wars have caused large migrations, changing the ethnic (and dialectal) picture of some areas—especially in Bosnia and Herzegovina, but also in central Croatia and Serbia (Vojvodina in particular).

[citation needed] The eastern Herzegovinian dialect is the basis of the Bosnian, Croatian, Montenegrin, and Serbian standard variants of the pluricentric Serbo-Croatian.

[14] Chakavian is spoken in the western, central, and southern parts of Croatia—mainly in Istria, the Kvarner Gulf, Dalmatia and inland Croatia (Gacka and Pokupje, for example).

Many dialects of Chakavian preserved significant number of Dalmatian words, but also have many loanwords from Venetian, Italian, Greek and other Mediterranean languages.

This dialect is spoken primarily in the federal state of Burgenland in Austria and nearby areas in Vienna, Slovakia, and Hungary by descendants of Croats who migrated there during the 16th century.

Kajkavian is mostly spoken in northern and northwest Croatia near the Hungarian and Slovene borders—chiefly around the towns of Zagreb, Varaždin, Čakovec, Koprivnica, Petrinja, Delnice and so on.

The division is partly based on religion – Serbia, Montenegro, Bulgaria and Macedonia (which use Cyrillic) are Orthodox countries, whereas Croatia and Slovenia (which use Latin) are Catholic.