Abstract
1. Introduction
2. Historical path of -yo
3. Previous studies
3.1 Hwang(1975)
3.2 Sohn(1986)
3.3 Kim(1998)
4. Methodology
4.1 Procedures
5. Results and discussions
5.1 Strangers
5.2 Friends
5.3 Intimates
6. Conclusion
Reference