It has been abundantly demonstrated that discrepancies (grammatical, lexical, pragmatic, etc.) between the mother tongue (LI) and a foreign language (L2) are the most serious cause of error among foreign-language learners. If this is so, the same foreign language may present different difficulties (and know different types of deviation) according to the learner's mother tongue. Accordingly Portuguese learners of English tend to make specific errors imposed upon their L-2 production as a result of L-l interference. A way of counteracting local tendencies could be the development of locally-orientated pedagogical materials and methods and so fight local areas of error more effectively.