Negotiating Lexical Uncertainty and Speaker Expertise with Disjunction

Abstract

There is a well-known preference for disjunctions XorY to be construed so that X and Y are semantically disjoint. However, there are two felicitous usage patterns in which the speaker violates this preference in part to convey information about the language itself. First, disjunctions of terms in a one-way semantic inclusion relation, such as boat or canoe, can form part of a speaker strategy to manage lexical uncertainty surrounding the two terms, or block unwanted implicatures that the listener might draw from the general term alone. Second, disjunctions of synonymous terms like wine lover or oenophile can be used to convey definitional information. We explore both of these uses, relying on corpora to obtain a fuller picture of their motivations and their effects on the listener. In addition, we show how both these uses are predicted by a standard semantics for disjunction and a recursive probabilistic model of communication in which speakers and listeners simultaneously exchange information about the world and about the language they are using. We also use the model to begin to formally characterize the pragmatics of implicature cancelation or blocking.