Abstract
In recent years, the growing number of Turkmen students enrolled in higher education institutions in Kazakhstan has posed new methodological challenges in teaching Kazakh as a cognate language. Although Kazakh and Turkmen are typologically related, differences in their phonetic, morphological, lexical, and graphemic systems result in systematic language interference that undermines the cohesion and coherence of students’ written academic discourse. This study aims to identify interference-related errors in the written texts of Turkic-speaking (Turkmen) learners of Kazakh and to examine their impact on textual cohesion and coherence. The study adopts a mixed-methods research design combining qualitative and quantitative approaches. The empirical data consist of summary texts produced by A1-level Turkmen students at a Kazakhstani university. Interference-related errors were identified through Error Analysis, supported by a comparative-typological analysis of Kazakh and Turkmen. Textual cohesion and coherence were examined using discourse models proposed by Halliday, Hasan, and van Dijk. The findings indicate that language interference is systematic and operates across multiple linguistic levels. Morphological interference weakens intersentential grammatical relations, particularly in the use of case, possessive, and personal markers. Graphemic interference, including the mixing of Cyrillic and Latin scripts, further reduces the academic acceptability and readability of students’ written texts. Overall, the study demonstrates that interference should be understood not merely as a set of isolated linguistic errors, but as a cognitive–discursive phenomenon that directly affects the quality of written discourse. These findings underscore the pedagogical value of translanguaging and contrastive instructional approaches for teaching Kazakh to Turkic-speaking learners.