Bulgarian is, unsurprisingly, the language of Bulgaria. Is it also the language of Macedonia?
Macedonia has one official national language: Macedonian. But Bulgarians claim this to be a Bulgarian dialect.
In the 19th century, the view that Macedonians spoke Bulgarian was all but universal (unless they spoke Greek of course, which is a different language altogether). It wasn’t until the 20th century that Macedonia, having become part of Yugoslavia, developed a separate language and literature. This didn’t occur spontaneously, but sprang from political motives: the Yugoslavs wanted Macedonian to resemble Bulgarian less than it had done so far. In practical terms, this implied that it was to become more like Serbo-Croatian, the majority language of Yugoslavia.
Even nowadays, Macedonians and Bulgarians have little trouble understanding each other’s languages. But the same is true for many other neighbouring peoples, such as the Czechs and the Slovaks, the Norwegians and the Swedes, and the Ukrainians, the Belarusians and the Russians. The mere fact that Macedonian and Bulgarian are mutually intelligible does in no way make Macedonian less legitimate a language. Bulgarians had better come to terms with that.