The influence of socioeconomic background, sex, and clinicians' race on the frequency of implementation of nonstandard phonological and grammatical structures was examined in 72 black preschoolers. In order to generalize findings to typical clinical settings, language samples were elicited by 3 black and 3 white clinicians using spontaneous, paragraph completion, and sentence repetition procedures. Results showed that socioeconomic status and sex had a strong effect on black children's usage of nonstandard phonological and grammatical forms. More striking, data suggested that the beginnings of a bidialectal capability were identifiable in the clinical setting in four- and five-year-old black children. Discriminant analysis detailed those nonstandard phonological and grammatical forms which contributed to dialect differences between lower and middle-socioeconomic black children.