In foreign language learning, a number of challenges are often encountered due to semantic and structural differences between the native language and the language to be learned. In this context, one of the challenges that native Turkish students face in learning Russian is the learning of indefinite pronouns in the Russian language. The study of the resulting differences of these pronouns in terms of semantic, functional, and structure, compared to indefinite pronouns in Turkish, comes across as a current problem in Russian learning and teaching. Grammar research shows that the general characteristics of indefinite pronouns in languages with different systems are not adequately investigated. Due to the structural characteristics of languages, the fact that there are significant interlingual differences in the pronoun concept, in particular, is one of the issues to focus on in language teaching and learning. For example, classifying a word as a name or adjective in another language, which is classified as an indefinite pronoun in the Russian language, causes a learning challenge in foreign language education learned using the comparison method. In this paper, studies of the definition, classification, and functions of indefinite pronouns were carried out through the work of linguists who researched the Russian language. For a better understanding of the subject, indefinite pronouns are structurally divided into 4 different groups in our study, based on prefixes or suffixes they receive: Indefinite pronouns used with the preposition -нибудь (-либо), indefinite pronouns used with the preposition -то, indefinite pronouns with the preposition кое-, indefinite pronouns with the prefix не-. The classified pronouns are exemplified by excerpts from the works of leading authors of Russian literature, Turkish translations of these sentences, and sentences created by us.
Keywords: Grammar, Russian Language, Pronoun, Indefinite Pronoun, Classification.