This study investigates the structural and functional differences between the non-standard Negro English of northern ghetto areas (NNE) and standard English (SE). The major field work was done in Central Harlem with (1) a geographically random sample of 50 pre-adolescent speakers in Vacation Day Camps, (2) six pre-adolescent and adolescent peer groups in Harlem, studied in individual interviews and group sessions, and (3) a random sample of 100 adults, in a middle-class area and two working-class areas. The linguistic analysis in this volume shows NNE related to SE by differences in low-level rules which have marked effects on surface structure. The -ed suffix, for example, is affected by rules of consonant cluster simplification; systematic variation of such clusters regularly differentiates past tense clusters from stem clusters, and also registers the strong effect of a following vowel in preserving the cluster. NNE is found to have no third singular -s or possessive suffix, but to have an intact plural -s. The absence of the copula is considered the result of regular phonological rules which remove single consonants remaining after contraction. A NNE negative concord rule distributes the underlying negative particle more consistently and to a wider range of environments than in white non-standard English. Repetition tests showed that many NNE speakers understand both NNE and SE forms but produce NNE forms. See AL 001 822 for Volume II. (Author/JD)