Review of the supervisor of the Bachelor dissertation by Ju. A. Gajdukova  «Early stages in the development of Russian nominal morphology by twins»  Principal Bachelor program for the direction 45.03.01 «Philology»  The work by Julia Gajdukova might seem very simple in its design and fulfilment; however, such impression is false. It is based on unique language material – a longitudinal study of the speech production of two twin-sisters. This is a special kind of data called «case study» in psycholinguistics. This dissertation is a very important brick in the basement of our knowledge about the nature of the acquisition of Russian by children  The statement of the problem has to do with the impression that twins do not care a lot about social contacts with other family members except their sisters or brothers due to the especially close speech and social connections with the latter. Therefore they frequently demonstrate some delay in language development and sometimes they even produce a special clandestine language that they use inside the dyad. It also happens frequently that twins can speak simultaneously without any rehearsal continuing the thoughts and summing up the sentences of each other (see the interview of adult twin sisters videotaped in Perm https://www.youtube.com/watch?v=6TBR8gx33CI). All these mysterious and not properly explained facts are waiting for explanation and research.  	To fulfil this work, Julia should get acquainted with the formalism of CHILDES system (what she has done by her own bootstraps) and use the possibilities of this system to compare her data with the data of other longitudinal studies of CHILDES and Child Data Corpus collected for many years by the researchers in the State Pedagogical University of Russia and in the Institute of Linguistic Studies of the Russian Academy of Sciences.  	Not evaluating the dissertation, I must say that I am very happy with Julia's devotion, her evaluation of the data, her attention to details that makes her data a solid basis not only for her own work but for the use of it by other scholars. This is a solid and unique material.    Dr of philology, Prof. Of the Chair of Russian Language Philological Faculty of SPbSu  Head of the department of Grammar Theory ILS RAS M.D. Voeikova