Communicative Efficiency, Uniform Information Density, and the Rational Speech Act Theory

One major class of approaches to explaining the distribution of linguistic forms is rooted in communicative efficiency. For theories in which an utterance’s communicative efficiency is itself dependent on the distribution of linguistic forms in the language, however, it is less clear how to make distributional predictions that escape circularity. I propose an approach for these cases that involves iterating between speaker and listener in the Rational Speech Act theory. Characteristics of the fixed points of this iterative process constitute the distributional predictions of the theory. Through computer simulation I apply this approach to the well-studied case of predictabilitysensitive optional function word omission for the theory of Uniform Information Density, and show that the approach strongly predicts the empirically observed negative correlation between phrase onset probability and rate of function word use.