Serbo-Croatian (sûr´bō-krōā´shәn), language belonging to the South Slavic group of the Slavic subfamily of the Indo-European family of languages (see Slavic languages). Serbo-Croatian comprises several dialects, one of which (Stokavian) has given rise to modern standard Serbian, which is spoken mainly in Serbia and written mainly in a form of the Cyrillic alphabet, and modern standard Croatian, which is spoken mainly in Croatia written in a modified version of the Roman alphabet. The other dialects are mainly found in parts of Croatia and Bosnia, and the predominant pre-1990s dialect in Bosnia and in Montenegro was the same as that of modern standard Croatian. Traditionally, the dialects of Serbo-Croatian had a regional and historical basis instead of an ethnic one, but no true national Yugoslav language ever existed despite efforts by some to develop one. The political domination of Yugoslavia by Serbs, the reaction against that, and the breakup of Yugoslavia into more ethnically based nations has led to a greater emphasis on the differences (some of them introduced) between dialects as a mark of national and ethnic identity, particularly among Croatians and Bosniaks, and led Serbs and Croats living in Bosnia and Herzegovina to use modern standard Serbian or Croatian respectively. The tendency now is to speak of Bosnian, Croatian, and Serbian languages, though those tongues remain largely mutually intelligible, a hallmark of dialects. The various forms of Serbo-Croatian are the native tongues of more than 18 million people in present-day Serbia, Montenegro, Croatia, and Bosnia and Herzegovina. Serbo-Croatian is not spoken to any significant extent outside these countries.
A feature that sets Serbo-Croatian apart from other Slavic languages is its use of musical pitch or intonation. It possesses four kinds of musical accent: two rising inflections, one long and one short, and two falling inflections, one long and one short. This musical intonation apparently reflects the earlier Indo-European pitch accent. Grammatically, Serbo-Croatian resembles Polish.
The oldest extant texts in Serbo-Croatian date from the 12th cent. For a number of centuries the literary language of the Serbs was a variant of Church Slavonic, and in Catholic Croatia it was usually Latin, although in the 13th cent. the Croats began to write down their spoken language. In the 19th cent. the Serbian philologist Vuk Stefanovíc Karadžić, through his writings and efforts, accomplished several major linguistic reforms. The most important one instituted the spoken tongue as the basis of the literary language. Karadžić also worked for a more phonetic spelling and consequently for a revision of the alphabet to that end. See also Yugoslav (South Slav) Literature.