Imagine an infant visiting the zoo with her mother. From her stroller, she observes a troop of capuchins on a nearby tree. Her mother points to the scene and says, “Look! The monkeys are grooming each other!” How might she come to understand that her mother’s arbitrary auditory signals represent something about a scene that she is witnessing? How does she parse the continuous actions of the apes to derive appropriate units of meaning such as agents or actions from this complex, dynamic event? And how might she make the correct assumptions about how the words relate to the unfolding events before her? Despite recent advances, much of the current debate centers on the classical questions of how infants map words onto the dazzling array of sights and sounds in their world and how this process is guided by development and experience. Indeed, the fi eld is still pondering possible solutions to the problem of ambiguity or indeterminacy of reference that was introduced by Q uine in 1960 as a philosophical conundrum. Given the complexity of the world, how is a language learner to know that a foreign word such as gavagai, uttered while a rabbit scurries by, refers to the entire rabbit rather than to the fur, ears, or ground on which it thumps. With no constraints guiding the learner, would she ever converge on the correct mapping of word to world?