The monograph considers three traditions that have typological similarities as historically isolated from the main linguistic and cultural array to which they originally belong. Each of the traditions under consideration is either in a foreign language and foreign ethnic (Russian Old Believers in Romanian Dobruja; Gradishchansky Croats in Austria), or a non-confessional (Bosnian Muslim) environment. This existence of the enclave determines an important typological pattern - the preservation of archaic features in language and culture as a way of self-identification, and this applies to all three considered traditions, regardless of the fact that Russians in Romania and Croats in Austria are resettlement ethnic groups, and Bosnian Muslims can be considered an "island" only conditionally - on a confessional basis. The appearance of numerous borrowings in the language and folk spiritual culture from the traditions of the countries on the territory of which the Slavic peoples live - Russians (in Romania) and Croats (in Austria) - is also accompanied by a number of typologically similar processes and phenomena.