Sistema e variação: quão sistemático pode ser o sistema linguístico num modelo baseado no uso?

This paper argues that a usage-based model implies a concept of language as a complex dynamic system which correlates social and cognitive aspects. In descriptive terms, a usage-based model implies the inclusion of language-internal variation in the study of any linguistic expression and its correlation with conceptual meaning. In methodological terms, a usage-based model implies using empirical multivariational methods, such as sociolectometrical methods. On a metatheoretical level, a usage-based model implies the de-systematization of the linguistic system and the construction of a multifactorial model of the grammar. It shows how Cognitive Sociolinguistics, an extension of Cognitive Linguistics, as a model orientated towards meaning and use is able to address these implications. To illustrate this argument, the results of socio-cognitive and sociolectometrical research into divergence between European and Brazilian Portuguese will be presented.