The article is focused on the several aspects of the G. Guillaume's theory, and, in particular, on the concept of "language mechanism", the question of using such terms as "morphological" and "syntactic"; as well as the problem of the hierarchical demarcation of parts of speech, and strict separation of “language” from “speech” are critically analyzed. In addition, special attention is drawn to the fact that the study of correlation between the language forms and the real objects, apart from psychosistematics, has always been in the focus of attention of linguists and most clearly manifested in the confrontation between nominalists (forms) and realists (objects).