Between grammar and discourse: the emergence of the discourse-marking function of acerca de in Portuguese

Abstract

This article analyzes the construction acerca de in Portuguese from a diachronic and functional perspective, with the aim of describing its trajectory of constructional change and the emergence of textual and discursive uses that have not been systematically addressed in the grammatical tradition. Grounded in Usage-Based Functional Linguistics and Diachronic Construction Grammar, the study examines data drawn from historical and contemporary corpora, covering occurrences of Portuguese from the fourteenth to the twenty-first centuries. The analysis considers parameters such as syntactic–semantic scope, structural position, clausal integration, and pragmatic–discursive contribution. The results reveal a gradual process of functional expansion, whereby acerca de ceases to operate exclusively at the subclausal level, introducing nominal and verbal phrases with referential value, and comes to scope over finite and non-finite clauses, as well as broader discourse segments. This trajectory involves host-class expansion, an increase in scope, and the growing proceduralization of the construction. In light of the criteria proposed by Traugott (2022), it is argued that, in contexts of topicalization and information-structure organization, acerca de can be characterized as a discourse marker, operating in the left periphery of the utterance and encoding interpretive instructions for the addressee. It is concluded that such uses reflect a process of textualization and functional abstraction compatible with contemporary models of pragmatic–constructional change, thus extending the description of the syntactic and discursive behavior of the construction in Portuguese.