This evaluation study on tandem learning among future teachers of Russian in school-based internships aims at examining the development of teacher language competences for institutional Russian teaching. The focus is on development of competencies of L2teachers in student teacher internships. The article deals with the tandem-method as one of the ways of training teacher language for educational purposes in the classroom. Teacher language always has didactic implications. The teacher serves as an educational role model in his foreign verbal actions, but the level of command of the language for using it professionally as teacher language in university internships is very heterogeneous. The reasons are manifold and related to worldwide migration and the efforts of reforming the educational system in Europe. That is why the subject of interest for this research is the development of teacher language as a part of linguistic competence. The individual perception of future Russian teachers of the functional logic and quality of tandem language learning and support is examined on the basis of learning diaries and interviews. The paper concludes with discussion