The article is devoted to the study of the functioning of youth slang in modern Polish and to clarifying the relationship between the linguistic norm and variation within this dynamic lexical subsystem. Youth slang is considered an important sociolinguistic phenomenon that reflects the linguistic creativity of the younger generation, its values, communicative needs, and aspirations for linguistic identity. Particular attention is paid to the sources of the formation of slang units, among which foreign borrowings, semantic transformations, word-formation models, as well as the influence of the digital environment and online communication play a significant role. The article analyzes the main tendencies in the development of youth slang in the Polish-speaking environment and outlines its stylistic, functional, and pragmatic characteristics. It has been determined that youth slang is formed under the influence of sociocultural factors, mass culture, media, and interlingual contacts. It has been established that slang performs not only expressive and identificational functions but also contributes to the formation of group solidarity, informal communication, and distancing from the official linguistic norm. At the same time, it is emphasized that the boundary between normative vocabulary and slang units is variable: certain elements of youth speech gradually integrate into broader language use, spread beyond the youth environment, and may acquire the status of generally accepted lexical items. The methodological basis of the study includes descriptive, comparative, and contextual methods of linguistic analysis. As a result of the research, the key mechanisms of variation of slang units, their structural and semantic features, as well as their role in contemporary linguistic processes have been identified. It is concluded that youth slang is an important factor in language dynamics that reflects sociocultural changes and contributes to the continuous renewal of the lexical system of modern Polish.