10.17192/ziaf.2025.5.1.8907 Gubina, Alexandra Alexandra Gubina Fiedler, Sophia Sophia Fiedler Zur Kooperation in informellen L2-Lernsettings Funktionen von Code-Switching in Sprachtandems und Peer-Interaktionen Zeitschrift für Interaktionsforschung in DaFZ : Vol 5 No 1 (2025) Philipps-Universität Marburg 2025 cooperation Interaktionale Linguistik code-switching interactional linguistics Deutsch als Fremd- und Zweitsprache conversation analysis for second language acquisition Kooperation German as a foreign and second language conversations-for-learning Code-Switching Konversationsanalyse für den Zweitspracherwerb conversations-for-learning 2025-12-15 2025-12-15 de JournalArticle https://journals.uni-marburg.de/0009/2025/354/8907 urn:nbn:de:hebis:04-0009-2025-354-89078 https://doi.org/10.17192/ziaf.2025.5.1 https://journals.uni-marburg.de/0009/2025/354/8907/8907.png 2750-249X application/pdf This study focuses on the use of code-switching in the acquisition of German as a foreign and second language (GFSL) in conversations-for-learning (Kasper +amp; Kim 2015), specifically, in language tandems between L1 and L2 speakers, as well as in everyday L2 peer interactions among GFSL learners (sometimes involving L1 speakers). Our data show that code-switching is used to perform four major functions: (1) soliciting language-related assistance during word searches, (2) confirmation checks, (3) ensuring shared understanding and providing an explanation, and (4) providing didactic, contrastive explanations through analogy between German and another language. We conclude by discussing to what extent code-switching can be considered a cooperative practice, how switching to other languages can create opportunities for language learning, and outline possible questions for future research. 2750-249X Zeitschrift für Interaktionsforschung in DaFZ Vol 5 No 1 (2025)