We review evidence that language is involved in the establishment and maintenance of adult categories of facial expressions of emotion. We argue that individual and group differences in facial expression interpretation are too great for a fully specified system of categories to be universal and hardwired. Variations in expression categorization, across individuals and groups, favor a model in which an initial “core” system recognizes only the grouping of positive versus negative emotional expressions. The subsequent development of a rich representational structure (...) may require the integration of a verbal categorization system with a perceptual processing system that is category-agnostic. Such a model may reconcile many strands of apparently conflicting behavioral, physiological, and neuroscience evidence concerning our understanding of facial expressions of emotion. (shrink)