The pragmatics of semantic change: Modeling the progressive-to-imperfective shift

Abstract

We implement a computational model of the cyclic progressive-to-imperfective shift, wherein languages with a single imperfective marker grammaticalize new progressive markers that ultimately broaden in interpretation and displace the older imperfective. While Deo (2015) offers a model of this process within the framework of evolutionary game theory, her model ultimately ignores the semantics she takes such care to construct. Our model, conceived within the Rational Speech Act modeling framework, offers a different perspective, operating directly over the utterance semantics. We show how semantic change may be a function of changes in utterance cost—a reflection of morphological complexity or frequency-of-use—as it relates to pragmatic reasoning. Counter to claims that grammaticalization is a process of conventionalization of implicature, our model holds the denotations of aspectual markers static; what changes is how we reason about their use given their changing costs.