In the last two decades there have been many attempts to integrate all kinds of mobile devices and apps to support formal as well as informal learning processes. However, most of the available apps still support mainly individual learning, using mobile devices to deliver content rather than providing learners with the opportunity to interact with each other. To address this we have designed an app based on a highly interactive, ubiquitous and constructive learning approach. The app is called Guess it! Language Trainer and allows learners to share, assess and co-construct their foreign language knowledge. Learning contents are no longer delivered but integrated into versatile tasks. Even though these tasks are being performed individually by each player, the players’ interaction with the app performed affects the whole community of learners. The current research paper presents the first results of an ongoing research project using mobile apps to enhance the Foreign Language Learning in a compulsory German language course at a Spanish University. In our paper we will firstly describe a specific app (Guess it! Language Trainer) which has been used to support students’ independent language learning outside the classroom. Secondly, we will describe how the app encouraged students to get actively involved in their own learning processes and thirdly, how the teacher can use the information stored in the system to retrace and assess students’ language learning.