This article is devoted to the rhyme, which is not only the object of literary analysis and poetics, but linguistics. The linguistics of rhyme on the material of Finnish oral traditions is not sufficiently studied at the moment. There are just random articles which are devoted to rhyme as an object of poetics and literary analysis. The subject of the study deals with some circum-stances of rhyme’s origin and development. It is necessary to raise some related problems, which are associated with the research topic, namely: the interpretation and meaning of the terms “sacred” and “sacred text” in the context of modern science; basic consepts of phonostylistics as a branch of Finno-Ugric linguistics; place of rhyme in the language and style of Finno-Volgaic sacred texts; nature and sources of rhyme in oral folk art of Finno-Volgaic ethnic groups. The Syntax of these languages is characterized by a strict and fixed word order of the sentences. Sacred texts are characterised by the sentences rather extended by secondary parts, it is one of the constructive preconditions to the building of natural rhyme. Phonological expressiveness of language is necessary not only for creation, saving and transferring words and information. It is an essential condition for the emergence and performance of oral folk art in order to preserve it and to transfer to future generations. This linguistic phenomenon serves as an instrument of aesthetic, emotional, spiritual, and psychological influence on the behavior and perception of the individual.