An important part of the grammatical proficiency of students learning Turkish as a foreign language is the use of verb complements in terms of case suffixes used with verbs. The suffixes that determine the relations between nouns and verbs that make up the two main word categories of Turkish are case suffixes. Noun case suffixes, whose main function is to connect nouns to verbs, are one of the most difficult subjects for students learning Turkish as a foreign language. However, there are few studies on teaching noun case suffixes to foreign students. The aim of this study, which was prepared based on the deficiency in the relevant literature, is to determine the usage levels of noun case suffixes in the oral expressions of French bilingual Somalian students learning Turkish. The study group of the research consists of 25 Somalian students studying at the B1, B2 and C1 levels at Bursa Uludag University Turkish Teaching Center in the 2019-2020 academic year and voluntarily participated in this research. The data obtained within the scope of this research, which was designed as a qualitative case study, were analyzed according to the suffix category that provides the relationship between the noun case suffixes and the verbs in the sentence. Other functions of the noun case suffix that provide the connection between nouns and nouns, nouns and prepositions are excluded from the scope of the study. The research data obtained by the semi-structured interview technique were analyzed using frequency analysis, which is one of the sub-techniques of content analysis. As a result of the study, it was determined that 25 French bilingual Somalian students learning Turkish made mistakes at a rate of about half when using the verbs with case suffixes, and they used the nominative case with the least mistakes.