Abstract
This paper shows the relevance of an evolutionary model for the study of language change. We focus on a cognitive and usage-based approach to language change, namely the Theory of Utterance Selection developed by Croft (2000). Croft's evolutionary approach takes its inspiration from neo-Darwinian evolutionary theory, particularly the Generalized Theory of Selection developed by Hull (1988), a philosopher of science. Language is viewed as a system of use governed by convention, and language change results from breaking with convention and propagating this innovation through the linguistic community until it becomes a new convention. Crucially, altered replication can be equated with language innovation, and propagation of individual changes is the linguistic counterpart of the differential perpetuation or selection of replicators. We will argue within the framework of Cognitive Linguistics (Geeraerts & Cuyckens, 2007) for a more systematic integration of cognitive and social factors in the explanation of language change. The mechanisms for language innovation are cognitive, as the pnnciples of cognitive efficiency like prototypicality constitute the main motivations for language change and metaphor and metonymy the main cognitive mechanisms of semantic change. The mechanisms for propagation are essentially social, including processes such as accommodation, identity and prestige. All of these mechanisms occur in individual communicative acts and operate like an "invisible hand" (Keller, 1994). We illustrate the sociocognitive evolutionary model of language change with some case studies on semantic change in Portuguese