Inferring word meanings by assuming that speakers are informative

•We present a model of how pragmatic informativeness can be used to infer word meanings.•Adult judgments about word meanings conform to model predictions.•Preschool children can also use informativeness to infer word meanings.

Language comprehension is more than a process of decoding the literal meaning of a speaker’s utterance. Instead, by making the assumption that speakers choose their words to be informative in context, listeners routinely make pragmatic inferences that go beyond the linguistic data. If language learners make these same assumptions, they should be able to infer word meanings in otherwise ambiguous situations. We use probabilistic tools to formalize these kinds of informativeness inferences—extending a model of pragmatic language comprehension to the acquisition setting—and present four experiments whose data suggest that preschool children can use informativeness to infer word meanings and that adult judgments track quantitatively with informativeness.