Abstract

It has been suggested that language disorders can serve as real windows onto language evolution. We examine this claim in this paper. We see ourselves forced to qualify three central assumptions of the the ‘disorders-as-windows’ hypothesis. After discussing the main outcome of decades of research on the linguistic ontogeny of pathological populations, we argue that language disorders should be construed as conditions for which canalization has failed to cope fully with developmental perturbations. We conclude that a robust link exists between developmental disturbances and evolutionary history that allows language disorders to be used as real windows onto the evolution of the neuronal substrate of language, and emphasize that our conclusion is more compatible with views of language evolution as the result of reorganizational changes as opposed to radically novel emergences.