The article presents the results of a sociolinguistic study of surzhyk in the speech of residents of the North‑Eastern region of Ukraine. The focus is on the main trends of communicative possibilities of surzhyk and its functional features in the situation of a multi‑code. It was found that the conscious use of surzhyk speech is a characteristic primarily of young speakers, who are able to realise its irregularity and use for a certain purpose, although in a limited range of situations. In situations of family communication, they use surzhyk as their ‘home language’. Such behaviour can also be a sign of a certain communicative ‘game’ when the speaker uses any language ‘image’ adapted to the specific needs of language communication. A diachronic analysis of the functional capabilities of surzhyk made it possible to reveal, on the one hand, its gradual ‘ageing’ as a functional first language, and on the other hand, its ‘getting younger’ as a conventional stylistic marker. Besides, its increased frequency in extra‑family communication has been recorded, which may indicate a gradual transition of the Russian‑speaking residents of Sumy to Ukrainian‑speaking forms of behaviour.