The paper looks at rules for discourse in the classroom and how they may complement or conflict with each other in facilitating the learning of language disordered children in the classroom or therapy session. Six critical skills are identified which children need for a good teaching-learning interaction. They are: attention, turn taking, coherence, repair (self correction), listener modification, and informativeness. Similarities and differences in styles in clinical discourse compared with classroom exchanges are noted. Problems which speech-language impaired children have in bridging these two styles of teaching-learning discourse is analyzed using an ethnographic study of the underlying rules of the interactions. Problems of the clinician studying the classroom include physical access, psychological access, and overcoming personal biases. Examples of direct (field notes, participant observation) and indirect (interviews, role play) methods of data collection are given. A case study of a 9-year-old communication disordered boy which uses the steps of the ethnographic method is offered. The steps are as follows: identify the child; describe communication problem; interview the child; develop a summary of the problem; observe in the classroom; summarize observations and determine pattern of communication breakdown; and, validate observations. Finally an intervention plan is developed by the clinician, the teacher, and the child. (DB)