This article follows a recent book from the same author, in order to consent a more general reflection on the hermeneutic instruments that can be used in interpreting multilingual international treaties. The analysis carried on in the present article shows that there are supplementary hermeneutic instruments which can be used to interpret multilingual international norms in order to solve the specific hermeneutic questions they pose. The core of the problem is that the interpreter interpreting this kind of norms faces a contrast of wills impossible to overcome. For EU secondary law this contrast is between the principle of uniformity of EU law, by one side, and the principle of the same legal value of versions in all official EU languages by the other side. Regarding international treaties, on the other hand, the contrast is between the wills expressed by the same State in a contradictory way, which is in re ipsa when texts in diverging languages are explicitly approved. In both cases the method of solution is the same: "going out" of the norm using supplementary interpretation instruments. These supplementary instruments, though, are not the same. In case of EU secondary law there is a specific instrument in order to find out the text in the language used to write and approve the source. For international treaties, not being possible the same (because of the procedure of approval of the text of the treaty) the solution is to recur to principles and fundamental values of international law system applicable ratione materiae to the controversial case
