This paper presents an evaluation of an exercise where CALL-SLT, a web-based spoken translation game, was integrated into in a Geneva middle school class. It shows how the usage of a CALL application as a complement to traditional school teaching can help pupils improve their productive language skills and how it can help them overcome their inhibition to communicate in a foreign language. In this paper the CALL-SLT platform and its adaption to a German textbook are described, as well as the experiment and results of integrating a translation game application on a middle school level.