The book of the outstanding scientist, specialist in the field of Slavic linguistics, professor A.M. Selishchev (1886-1942) shows the results of his observations of language activity during the revolutionary events of 1917-1926. These results indicate various deviations from the norms of the Russian literary language and the conditions, circumstances and consequences of such deviations. In detail, using a large number of sources, the distribution of the peculiarities of the speech of revolutionary leaders in communication, changes in the meaning of words, linguistic innovations among the working class, peasantry, and national minorities are described. The book will be interesting not only for students of comparative historical linguistics, but also for a wide range of readers. 2nd edition.