The following text presents the progress of a research work which belongs to the research line concerned on learning difficulties and mistake control. The main objective of this study is to illustrate the use of the personal dictionary of difficulties as a useful instrument to support difficulties in the learning and teaching processes of English as second language. The carried process was a collaborative work between both teacher and students. In addition, there is an emphasis on the immeasurable value of the student’s interlingua when reflecting on the processes of learning a foreign language. This becomes an essential instrument to reinforce students’ autonomy, along with the idea of learning how to learn, and moreover overpass the difficulties implied when writing a foreign language.