Abstract This tutorial discusses the theoretical and empirical framework and the potentially controversial assumptions within which research into language breakdown is being conducted. The focus is on questions that bear upon the relevance of studies of language pathology to linguistic theory. Issues concerning meta-theory are considered along with specific predictions related to acquired pathologies, specifically agrammatism, as well as to developmental language deficits, specifically, SLI, as well as research into a selective sample of other congenital disorders. We discuss issues such as the interpretation of Fodorian modularity, syndromes vs. case studies and brain plasticity, along with questions related to patients' diagnosis and the clinical and theoretical validity of syndromes. Review and discussion of specific hypotheses are restricted to the computational parts of language — syntax and morphology — excluding all other topics. The final section is a summary and a discussion of the current state of affairs with respect to linguistic studies of language breakdown.