this succint research we will start from the idea promoted as early as the Enlightenment era by the philosopher J.-J Rousseau in the eighteenth century. According to Rousseau, in the teaching process, the teacher must take into account not only the specifics of age or group, but also the individual ones. In other words, each student is entitled to an individual approach when studying. In this context we support the idea that contrastive analysis and error analysis can be useful both for teacher and student in the teaching/studying/evaluation process. Even the researcher Vigotskii was mentioning the close connection between language and speech. Therefore, the person who is learning a foreign language far away from a real context is first thinking in her native language and then formulating the structures in the foreign language. It is here that interferences occur, i.e. errors caused by modeling of structures from the native to the foreign language.