The basic claim of this paper is that the central competence of professional legal translators when translating legal terms and concepts is the ability to choose target text words that relevantly represent source text concepts. The criterion of ‘relevance’ is connected to the requirements of the target text communicative situation and the projected task of the legal translator to create a bridge which enables the expert target text reader to grasp the relevant aspects of the source text concept. In order to describe the elements of this task, I suggest viewing legal translation as an instance of knowledge communication that gives the translator the role of an intermediary agent. While the comparative process is a specific type of comparative law, the insights gained can be suitably presented and compared in the form of lexical frames. These characteristics and tools should be emphasized in legal translation didactics in order to offer students concrete steps to use when acquiring the complex competence of professional legal translators.