PECULIARITIES OF THE FUNCTIONING OF Ø AND -O-/-E- ALTERNATIONS DURING NOUN INFLECTION IN UKRAINIAN

The article is dedicated to studying sound alternations, particularly the alternation of the vowels -o- and -e- with a zero sound in the derivation process of nouns in modern Ukrainian. This alternation is an unstable yet widely used phenomenon that combines historical phonetic processes with contemporary morphological functions, including the formation of grammatical categories such as case and number. The study focuses on 37 nouns that exhibit deviations from the general trend: either the expected vowel omission does not occur, or, conversely, vowel omission is observed despite the lack of a systematic pattern. Understanding these alternations is critically important for foreign students, as it helps them avoid mistakes, develop linguistic intuition, and grasp the structure of the Ukrainian language. The article examines the peculiarities of teaching this topic to foreign students at different levels of language proficiency. A step-by-step introduction of the material is proposed, following the principle of grammatical minimum, with exceptions emphasized only as needed and following the learner’s proficiency level. In addition to theoretical conclusions, the article provides recommendations for the practical application of the findings in the educational process. A compiled table of exceptions will aid in the systematization of knowledge, serving as a reference tool for instructors and a visual aid for students. Additionally, lexical topics are suggested, within which each word can be introduced for study. The research was conducted using corpus linguistics methods, which allow for identifying a comprehensive list of exceptions, and analyzing the lexical content of various Ukrainian as a foreign language (UFL) textbooks. This approach made it possible to track trends in teaching this topic. The proposed findings can serve as a foundation for further improvements in the methodology of teaching Ukrainian as a foreign language, particularly for the development of specialized textbooks and learning materials that take complex morphonological features into account. Key words: vowel alternation with zero sound, Ukrainian as a foreign language, morphonological changes, corpus linguistics, phonetics teaching, grammatical minimum, teaching methodology.