This study explored the factors that lead college-level EFL adult learners to participate productively in speaking in a Content Based Instruction (CBI) course. Having investigated how the classroom tasks and environments scaffolded the learners to participate, the study considered factors for motivating students to engage in classroom discussion in spontaneous, voluntary speaking. The findings of this study are discussed through a sociocultural approach. Based on an analysis of the classroom observation and interview data, the study suggests that scaffolding devices and classroom environment play a significant role in encouraging and promoting output performance. The study suggests that four types of scaffolding should be available for a CBI course to facilitate participation in a spontaneous speaking mode: clear guidelines for comprehension and participation; tasks appropriate for the learners’ cognitive and linguistic level; an emotionally supportive environment formed by rapport among classmates; and instructional aids to increase motivation and willingness to participate.

1. INTRODUCTION
 2. LITERATURE REVIEW
  2.1. Content-Based Instruction (CBI)
  2.2. Output in L2 Learning
  2.3. Scaffolding
 3. METHOD
  3.1. Context of the Study
  3.2. Sources of Data
 4. RESEARCH FINDINGS AND DISCUSSION
  4.1. Comprehension Demand
  4.2. Anxiety Toward Participation
  4.3. Support from Fellow-Students
  4.4. Effects of a CBI Course
 5. CONCLUSION
  5.1. Clear Guidelines for Comprehension and Participation
  5.2. Tasks Appropriate for Cognitive and Linguistic Level
  5.3. Rapport with Classmates
  5.4. Instructional Aids for Encouraging Participation
  5.5. Limitations of the Study
 REFERENCES

• AeJin Kang(Sookmyung Women’s University)