The purpose of this series of four studies was to precisely describe the code and dialect features of the speech of both lower class Negro children and middle class white children. In the first study, 16 white middle class (WMC) children were compared to 16 Negro lower class (NLC) children on both an imitation and a comprehension task. The WMC subjects scored significantly higher on both tasks, even after the scores of the NLC subjects on the imitation tasks were improved by adjusting them for differences of dialect in the children's responses. No adjustment, however, was made for the administering of both tasks in standard English. The second study took free speech samples from 20 NLC and 20 WMC 5-year-olds to discover any possible linguistic code variations between groups. The WMC subjects showed a significantly superior range of syntactic structures, but there was no significant difference between groups in the use of specific types of complex sentences. The same free speech samples were then analyzed in the third study to find and list examples of nonstandard dialect variations of NLC. The fourth study developed a psycholinguistic model for measuring syntactic complexity in bot h quantitative and qualitative terms. (MH)