The term "Balkan language union" coined by Nick Troubetzkoy. And in 1958 in his work, Alexander Rosetti (Romanian linguist) argued that the similarity of the languages of the Balkans is quite large and can combine languages into one group. His colleague, Theodore Kapidan in his studies came to an even more meaningful conclusions. He proclaimed that Languages Balkan groups have a common basis. In the Balkan distinguish languages spoken directly to the Balkans, and the languages that are part of the Balkan linguistic union. In Russia, the study of Balkan languages involved in tv Tsyv'yan, which argued that the Balkan languages have a common grammar, and different sets of vocabulary. At the end of the last century, an Sobolev in his work pointed out that signs of word formation in the dialects Balkan languages groups are unevenly distributed, as well as the fact that their system varies, and there is no systemic features in their full kit. He developed a division of the Balkan languages into two groups: the eastern or the Bulgarian-Greek group and Western and Serbian-Albanian-Macedonian- group.
To date, there is a development project entitled "Small dialectological atlas of the Balkan languages, which is based on information about the Balkan language union. The composition of the Balkan linguistic union includes languages from different branches of the Indo-European language family. Thus, the Albanian language belongs to a group of Albanian language, Greek – the Greek group, Romanian, istrorumynsky, aromunsky and Meglena-Romanian are Romance, Romany language – to the Indo-Aryan group, and the Serbian, Croatian, Bulgarian and Macedonian languages are part of the Slavic group.