摘要：The definition of theme is not entirely uncontroversial within systemic linguistics. Furthermore, the application of the notion of theme to languages other than English is even more problematic. Portuguese is one such a language, not only because of its specificity, but also because, depending on the definition of theme, its two main varieties may not go entirely together when it comes to what is marked or unmarked. The purpose of this paper is to raise arguments for a definition of theme that may also be useful for languages such as Portuguese, where the subject is often elided leaving the predicator as clause initial. The structure shown by this type of clause and the way it casts doubts on the organisation of the clause as message, seem to be related to the core of the controversy over the definition of theme.
