This project is issued from a project proposal concerning eye-tracker and the willingness to make a language study case, the main hypothesis of the project is: "Can a tool using eye-tracking assist and train adult learners of Danish to understand Danish texts?". The study of the reading mechanisms and the methods to learn a language have been the first step in the project. Then several parts have been reviewed and considered for the development of the future tools such as the device that will be used but also some knowledge concerning teaching to adults. A user centric design study has been done to have a convenient application for the learners using two low fidelity prototypes which lead to a final design. The implementation follows as close as possible the prototype. Some user tests have been done to get a general impression about the system. Those tests provides some clues about the fit between the assumption and the actual needs of the Danish learners and such a system could potentially assist to understand a text, however concerning the training part of the hypothesis longer tests are required to have an answer.