As part of a longitudinal study, the conversational skills of 67 deaf adolescents were assessed in spoken English, simultaneous communication (SimCom) and American Sign Language (ASL). Two groups of students were identified on the basis of the communication used in their current educational program: a small group of 16 students in programs using spoken English (oral) and a larger group of 51 students in programs using sign communication (bimodal). Students in spoken English programs had good spoken English skills and limited ASL skills, whereas the reverse was true for students in bimodal programs. Most students demonstrated sufficient skill in one or more systems to meet basic interpersonal communications needs, but not those required for advanced academic discourse. In neither group was spoken English related to ASL skill. SimCom skills were strongly related to spoken English in the oral program group and to ASL in the bimodal program group. Spoken English in adolescence was highly predictable from spoken English in early childhood. Within the bimodal program group, students with deaf parents had better SimCom and ASL skills than those with hearing parents. Among bimodal program students with hearing parents, better SimCom skills (but not ASL skills) were associated with earlier introduction to sign communication in school and to mothers' use of sign communication.