Telecollaboration has been applied in foreign language education for more than two decades. This corpus study on telecollaboration in Third Language Learning has been carried out in institutional (CEFR) and non-institutional settings following the principle of autonomy in the framework of Higher Education implementing online tandems and student recordings in order to analyze discourse patterns. The chapters of this issue are original studies on corpus data of the L3Task project reflecting findings and new research paradigms and instruments that consolidate teaching and research methodology on online tandem practice for third language learning.