Linguists have mapped the topography of language behavior in many languages in intricate detail. To understand how the brain supports language function, however, we must take into account the principles and regularities of neural function. Mechanisms of neurolinguistic function cannot be inferred solely from observations of normal and impaired language. In The Neural Architecture of Grammar, Stephen Nadeau develops a neurologically plausible theory of grammatic function. He brings together principles of neuroanatomy, neurophysiology, and parallel distributed processing and draws on literature on language function from cognitive psychology, cognitive neuropsychology, psycholinguistics, and functional imaging to develop a comprehensive neurally based theory of language function.
Nadeau reviews the aphasia literature, including cross-linguistic aphasia research, to test the model’s ability to account for the findings of these empirical studies. Nadeau finds that the model readily accounts for a crucial finding in cross-linguistic studies--that the most powerful determinant of patterns of language breakdown in aphasia is the predisorder language spoken by the subject--and that it does so by conceptualizing grammatic function in terms of the statistical regularities of particular languages that are encoded in network connectivity. He shows that the model provides a surprisingly good account for many findings and offers solutions for a number of controversial problems. Moreover, aphasia studies provide the basis for elaborating the model in interesting and important ways.