Paragrammatism refers to substitution errors in pronouns and verb tense. Paragrammatism differs from agrammatism in that paragrammatic errors are seen in fluent aphasias. While agrammatic speech is effortful and telegraphic with omission of function words such as prepositions, articles, conjunctions, as well as bound morphemes, the paragrammatic speech of fluent aphasics generally contains well-constructed sentences with errors in grammatical morphemes, and also substitution of lexical items. The difference in error types are theorized to be due to neurological deficits affecting different stages of sentence processing, with paragrammatic speech errors occurring later in the sentence formulation processing. Paragrammatic errors may or may not occur in writing as well as in speech due to: (1) presumed differences in the neural circuits responsible for the two functions, (2) differences in the organization of these skills in the brain, and (3) the...