Gradable adjectives, vagueness, and optimal language use: A speaker-oriented model

This paper addresses two issues that arise in a degree-based approach to the semantics of positive forms of gradable adjectives such as tall in the sentence “John is tall” (e.g., Kennedy & McNally 2005; Kennedy 2007): First, how the standard of comparison is contextually determined; Second, why gradable adjectives exhibit the relative-absolute distinction. Combining ideas of previous evolutionary and probabilistic approaches (e.g., Potts 2008; Franke 2012; Lassiter 2011; Lassiter & Goodman 2013), we propose a new model that makes exact and empirically testable probabilistic predictions about speakers’ use of gradable adjectives and that derives the relative-absolute distinction from considerations of optimal language use. Along the way, we distinguish between vagueness and loose use, and argue that, within our approach, vagueness can be understood as the result of uncertainty about the exact degree distribution within the comparison class.