Data on English article usage, based on a new classification system ("a,""the," and null article), were obtained from 20 adults and 20 two- and three-year-old children. An oral sentence completion technique was used with the child subjects, and the same items in written form were used with the adults. The results for the older children in the sample confirmed the results of previous studies in revealing a pattern of overuse of the definite article. However, the more complete usage data suggest that the overuse is a selective one that occurs predominately in one category and after a period of essentially correct usage. These findings argue against an explanation based on egocentrism and suggest that the incorrect usage of the more advanced children results from an overextension of a principle of shared knowledge found in adult article use. Overall, the data in this study allow description of an acquisition sequence for the English article system that extends earlier developmental findings and resolves some of their inconsistencies. (Author/GT)