Since speech pathologists are interested in the role nonfluent behavior may play in the onset or development of stuttering, this study compared the linguistic behavior of 17 fluent four-year-old children to that of 17 nonfluent children similar in age, intelligence, sex, sibling status, race, socioeconomic status, and education. The aspects of linguistic behavior studied were productivity (variability and redundancy) and grammar (variability and syntactic complexity). Speech samples, comparable for all subjects, were transcribed and segmented to provide data for comparisons of nonfluency and variability of productivity, and type-token ratio data were used for comparisons of redundancy of productivity between the two speaker groups. All comparisons of variability and syntactic complexity of grammar, except for lexical and function words, were made according to transformational generative grammar. The overall finding of the study was that fluent and nonfluent children were similar in speech performance except that communication units were shorter and morphological errors were more infrequent for the fluent children than the nonfluent children. The findings indicate that speech pathologists should not consider linguistic skill as an explanatory factor in fluency differences in young children. (Author/JM)