Yugoslavia

The language in Yugoslavia, i e in Serbia and Montenegro, is mainly Serbian. In Serbia there are two larger linguistic minorities, who speak Albanian (in Kosovo) and Hungarian (in Vojvodina). There are also minorities who speak other languages, e g Romani and Yiddish.

Serbian is a South Slavic language which is written in the Cyrillic alphabet, but it can also be written using the Latin alphabet.
There are two important dialects, "Ekavian" and "Ijekavian".

The language which earlier was called Serbo-Croatian and sometimes Croato-Serbian had several dialects. Serbo-Croatian as a literary language was not completely uniform, due to differences in historical and cultural background of the various Yugoslav republicss. Ingmar Söhrman writes (in: Språken på Balkan, in: Svanberg, I & Söhrman, I: Balkan, Arena 1996, pp.33-50) :

Today there is a deliberate ambition to promote the unique and different features of one's own linguistic variant.

Serbian, Croatian and Bosnian as standard languages will probably develop separately in the future.

Albanian is an Indo-European language, which forms its own subgroup within the Indo-European family, and thus isn't closely related to other IE languages.

Hungarian is a Fenno-Ugrian language, belonging to the Ugric branch of the Fenno-Ugrian language family (which is unrelated to the Indo-European). Related to it, albeit distantly, are Finnish, Estonian and Saami.