Parallels and divergences in the acquisition and dissolution of language.

Analyses of the relation between the acquisition and dissolution of language have typically focused on whether or not the forms of language dysfunction that result from brain damage correspond to specific stages of language acquisition: the Regression Hypothesis. These analyses have not met with great success: although there are a number of superficial similarities between aphasic disorders and different stages of the immature linguistic system, there are also important differences. I will suggest that a focus on the behavioral similarities between language acquisition and dissolution is unlikely to be productive. A more productive course would be to focus, instead, on the general principles that constrain the acquisition and dissolution of language.