1. Introduction and Background -- Academic Achievement -- Social Interaction -- Verbal Behavior in the Multiethnic Classroom -- This Experiment and the Study of Children's Language -- Categories of Verbal Behavior: Some Comments on their Rationale and Background -- 2. Method -- Population -- In-service Teacher Training -- Implementation -- Classroom Observations -- Dependent Variables: -- Pupil Academic Achievement -- Videotape Films of Pupils' Behavior -- Categories of Social Interaction -- Categories of Verbal Behavior -- 3. Results -- Academic Achievement -- Social Interaction -- Verbal Behavior -- Relationship between Pupil Behavior in the Discussions and their Academic Achievement -- 4. Discussion -- Academic Achievement -- Cooperative Learning, Achievement and Motivation -- Levels or Kinds of Achievement -- Cognitive Strategies and Pupils' Achievement -- The Relationship between the Discussions and Academic Achievement -- Verbal Behavior -- Cognitive Strategies -- Educational Environment as a Variable Affecting Children's Language