Bilingualism requires a reassessment, a redefinition in relation to new linguistic realities. Contrastive analysis returns, but it is viewed in terms of multilingualism and theory of mistakes/errors. We cannot put an equal sign between contrastive analysis and theory of errors. In foreign language didactics, “mistake” and “error” are two different concepts, the latter including the ignorance of rules. Learning another language does not mean starting from scratch, the previously learned languages contribute to the study of the new one. It is necessary to note and realize the similarities and differences to strengthen the knowledge of another language. If the two languages have similarities regarding their vocabulary, morpho-syntactic structures, students can make an amalgam of them, i.e. to confuse, this is how errors occur. This phenomenon is transient, and the process of tolerating and acknowledging the error represents a part of the process of learning a foreign language. The teacher should allow the students to take risks, to allow them to make errors, to accept them as proof/index of some language learning stages or as a result of the teacher’s/educator’s work.