Within the European TILA project a case study was carried out where pupils from schools in Finland and the Netherlands engaged in debating sessions using the 3D virtual world of OpenSim once a week for a period of 5 weeks. The case study had two main objectives: (1) to study the impact that the discussion tasks undertaken in a virtual environment have on the discussion skills and motivations of high school pupils, and (2) to explore how the presence of a peer from a different culture might influence the discussions and pupils' engagement. The discussion tasks in virtual worlds were very much appreciated by the participants. Telecollaboration, or the possibility to interact with pupils across borders, was found to have an additional motivational effect on pupils. Even if participants with varying linguistic resources may successfully work together in many authentic situations, telecollaboration in a Lingua Franca with focus on debates, for example, requires careful matching of the participants according to their proficiency levels. Otherwise the experience might increase anxiety levels of the less proficient pupils. [For full proceedings, see ED564162.]