This dissertation addresses a recently attested phenomenon in Brazilian Portuguese (BP): plural agreement between climate verbs (v.g. chover, ventar, nevar, trovejar) and locative/temporal topics within relative clauses. This phenomenon is investigated in the light of a proposal that aims at integrating generative linguistics and psycholinguistics procedural models, a line of investigation that has characterized the research developed at the Laboratory of Psycholinguistics and Language Acquisition at PUC-Rio (LAPAL). Subject-verb agreement is a robust process in natural languages and failures in the implementation of agreement have been treated in the psycholinguistics literature in terms of speech errors, not related to grammar knowledge. In order to investigate if agreement with climate verbs is occasional or licensed by the rules of BP, two experiments were initially conducted: an elicited production study and a self-paced reading test. The results indicate that (i) speakers really produce plural climate verbs in the context of relative clauses and (ii) the BP speakers accept the occurrence of these verbs in the plural within relative clauses (specially within non-standard relatives), what favors analysing it as a grammar option and not a mere speech error. Generative proposals are considered in order to provide an integrated analysis that can explain the phenomenon under investigation. This analysis seems to be consistent with the results of a grammaticality judgment task realized as part of a self-paced reading experiment. The rate of acceptability for climate verbs in the singular and plural has been contrasted to the rate of other three types of verbs (unergative, monoargumental and biargumental unaccusative verbs), always in the context of relative clauses. The results indicate that climate verbs differ from unergative ones (which will not allow agreement with locative / temporal topics) and are similar to unaccusative verbs (which effectively license agreement with a topic). The results are explained in the light of an Integrated Model of On- Line Computation (MINC). It is considered that plural agreement of climate verbs with a topic would be compatible to the notion of a core grammar with a marked periphery, characterizing an innovative BP grammar.