Why are Bosnian, Croatian, Montenegrin, and Serbian treated as separate standard languages?

Bosnian, Croatian, Montenegrin, and Serbian are treated as separate standard languages primarily due to political and national identity rather than linguistic divergence. While educated speakers from these regions can converse with full mutual understanding, the breakup of Yugoslavia in the 1990s led each new state to establish its own distinct language standards to reinforce national sovereignty.123

The separation is maintained through several practices:
* Standardization: Each country now manages its own language standards, with standardizers in one nation no longer consulting those in others.1
* Writing Systems: Differences are most visible in written form, with Serbian favoring the Cyrillic alphabet and Croatian, Bosnian, and often Montenegrin utilizing the Latin alphabet.123
* Vocabulary and Purism: Nations employ linguistic purism to differentiate their standards, sometimes proscribing words perceived as belonging to a neighboring state's version of the language.1

Ultimately, while they share a common linguistic foundation, no joint standard exists, and the identification of the language is tied to the speaker's ethnic and political affiliation.123