[Colloquium] The Puzzle of Learning Disjunction

To understand language, we rely on mental representations of what words mean. What constitutes these representations and how are they learned? To address this question, I discuss the puzzle of learning the disjunction word “or”. I present experimental studies that show preschool children (3-5 years old) can interpret “or" as inclusive disjunction. I also present the results of a corpus annotation study that shows the exclusive interpretation is much more common in child-directed speech. These two findings confirm a puzzle in the current literature: How can children learn the inclusive interpretation of “or" if they rarely hear it? My proposal is that exclusive interpretations in child-directed speech correlate with interpretive cues such as intonation and the semantic consistency of the disjuncts. Applying a supervised machine learning technique, I check the reliability of these cues and demonstrate that an ideal learner can use them to learn both inclusive and exclusive interpretations of disjunction from child-directed speech. Together, these studies provide evidence for a more sophisticated word learning mechanism as well as richer and more context-dependent representations of functional meaning than previously assumed.