The article is devoted to language competence study of higher education institutions’ students as the basis of professional language culture. It was emphasized that students of higher education should develop language competence, follow the literal language norms, avoid morphological, lexical and phonetic violations. Mastering the Ukrainian language perfectly is the task of every conscious citizen, who is obliged to be able to use all the lexical wealth in the professional language. The theoretical basis of language competence is substantiated, it is emphasized that it should not be confused with communicative competence. Various aspects of research by scientists regarding language culture, language norms, language and stylistic advice aimed at improving the language of professional communication are highlighted. Violations of lexical norms in the students’ professional language were revealed. The most typical lexical errors were analyzed: 1) inappropriate use of paronyms. Such words should be checked in the dictionary of paronyms; 2) the use of pleonasms, excessive or redundant words and repetitions (tautologies); 3) the use of lexical Russianisms, which violates lexical norms, litters the literary form of the Ukrainian language, leads to mistakes regarding the use of tracing foreign words, surzhyk (mixed language dialect); 4) using words in a noncharacteristic or context-inappropriate meaning; 5) literal translation of phraseological units, words with a phraseologically related meaning, which have their counterparts in the Ukrainian language, or violations of phraseological accuracy; 6) inappropriate use of borrowed vocabulary, in particular anglicisms that have their counterparts in the literary language. A foreign word can be determined by phonetic-grammatical design and lexical meaning; 7) incorrect use of prepositional structures, which arises due to insufficient knowledge of the Ukrainian prepositional patterns. When translating the conjunction with the preposition “po” from Russian, one should take into account the peculiarities of prepositions’ use in the Ukrainian language, and not translate verbatim. Work on lexical errors’ elimination will make it possible to improve the language culture of students, to form language competence, and to observe the literary language norms.