The article deals with one of the disciplines of Soviet linguistics called by its authors “social dialectology”, but which, according to specialists in the history of linguistic ideas, could be seen as a precursor of the modern sociolinguistics. The article studies theoretical frames of this social dialectology especially by the point of view of its object, the speech of proletarians. The data and conclusions of this study can be useful when studying the history of linguistic ideas in the early 1920-1930’s that would have developed in the same historical and cultural conditions as early Soviet literature.