This study investigated the effects of interference of a native dialect in the acquisition of a second dialect. Four groups of subjects were used: Five white preschool children from an intergrated nursery school, five Black preschool children from a Head Start program, five white, middle-class 16-, 17-, and 18-year-olds, and five Black 16-, 17-, and 18-year-olds from the University of Cincinnati's Upward Bound program. Subjects listened to a tape of twenty sentences, ten in Black dialect and ten in Standard English, and were asked to repeat what they heard. The changes or errors were evaluated according to the nine factors listed by Baratz (1969). The study found that: (1) native speakers can reproduce their own dialect better than non-native speakers; (2) each group experienced a significant amount of interference from their native dialect in an attempt to speak the second dialect; (3) both groups at the same age level made approximately the same number of changes with their native and second dialects; and (4) neither Black nor white children are usually bi-dialectal, but competency increases with age. (Author/AM)