Tajik is an under-resourced language from the point of view of the intonation systems description, so the available descriptions of this system can’t be used in the comparative linguistic studies. Since some researchers consider the intonation systems of Tajik and Persian to be identical, the use of the description of Persian intonation could be the solution for the issue, but the question of whether these systems are really identical remains open. The article deals with the problem if the choice of the Persian intonation description (by Nami Tehrani) for the research of Russian-Tajik intonation interference was acceptable and to what extent.