The relationship between various aspects of mother-child interaction and the language performance of young disadvantaged Negro children is assessed in this study. An exploratory survey was conducted to determine if mothers in socially disadvantaged families were willing to enter a parent participation preschool program. Subjects for this study, selected from families who were willing to participate, were 53 children ages 2 1/2 to 3 1/2 years, second or later in birth order, and their mothers. Data were collected by language testing and by structured order, and their mothers. Data were collected by language testing and by structured observation of mother-child interaction scored by two raters on various scales. Significant positive correlations were found between the language test scores and the mothers' acceptance, use of praise, and rewarding of independence, and the child's independence and verbal initiative. Mothers' negative actions such as use of criticism and discouragement of verbalizations were reflected in children's lower scores in language performance. Some sex differences were shown in test scores and in mother-child interaction. Much variation was shown among the sample children. Recommendations are given for the use of the measure of Mean Length of Utterance. (NH)