Fuzzy if-then rules are used to represent fuzzy models. Real data is later used to tune the model. Usually this forces a modification of the initial linguistic terms of the linguistic variables used for the model. Such modifications may lead to a loss in interpretability of the rules. In this paper we suggest using a form of multiresolution to tune the rules, by introducing more linguistic terms in the regions of the universe of discourse where this is needed. Starting with triangular shaped

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... guistic terms and recalling that symmetric triangles are first degree splines, a form of multiresolution is readily obtained, supporting a better accuracy of the model. It is shown that by using the linguistic modifiers "very" and "more or less" as well as the metasemantic modifiers "between" and "from -to" the interpretability of the original rule may be preserved.