CroatianSerbianBosnianMontenegrin

Croatian, Serbian, Bosnian, and Montenegrin are standard varieties of a pluricentric South Slavic language commonly referred to historically as Serbo-Croatian. They are built on a common South Slavic core, largely derived from the Shtokavian dialect, and share much grammar and core vocabulary, which gives a high degree of mutual intelligibility among speakers.

Historically, the language was often treated as a single whole during the 19th and 20th centuries. After the breakup of Yugoslavia, the four national communities began to standardize their own varieties, resulting in four codified standard languages: Croatian, Serbian, Bosnian, and Montenegrin. Each has its own normative bodies, literary tradition, and terminology preferences, reflecting national identities while retaining substantial linguistic overlap.

Linguistically, the standards differ in phonology, vocabulary, and orthography. A key area of variation concerns the reflex of the historical yat vowel, leading to Ikavian, Ijekavian, or Ekavian variants across the standards. There is also variation in lexicon and stylistic norms, such as preferred terms in institutions, media, and education. Despite these differences, speakers of the four standards usually understand one another with little difficulty in everyday communication.

Scripts and orthography vary by country. Croatian uses Latin script as the official standard; Serbian uses Cyrillic as the official script alongside Latin. Bosnian and Montenegrin standards generally employ both scripts, with Latin more prevalent in everyday use in Bosnia and in Montenegro. The relationship among the four varieties remains closely tied, balancing shared heritage with distinct national standards.