To establish normative standards against which to contrast the speaking performance of aphasia patients, a sample of 54 adults representing a broad range of age and education were administered the picture cards of the Thematic Apperception Test to stimulate speech. The stories thus elicited were tape recorded. Each word spoken was grammatically classified. The data demonstrated the existence of highly consistent individual differences among normal speakers in the relative frequency with which they used various grammatical classes. By factor analysis six dimensions of individual difference were defined. A group of 24 aphasia patients also responded to the pictures. Analysis of their speech suggested that grammatical class usage and the dimensions represented by the factors"descriptive specificity" and "richness of vocabulary" were appropriate measures for differentiating speech of aphasia patients, as well as normals, and for characterizing change over time in recovering aphasia patients. (KB)