This entry delineates the three types of discourse and some of their implications for the corresponding notions of ‘problem’: PROBLEM1, PROBLEM2 and PROBLEM3. No attempt will be made to distinguish between different levels of problem (e.g. problems of reception vs. problems of production), or different phases of the translation process where a problem may manifest itself, or any other aspect of translation problem, specific to certain genres, text-types, media (e.g. lip synch in dubbing) and even to individual texts.