In this paper I suggest, following Haspelmath(2000) that -ko in Korean is a conjunction verb or converb which functions a subordinator or complementizer(-ko1 and -ko2) or a coordinator(-ko3), these three subtypes of -ko all being allomorphs of a converb -ko. Its function is not inherent but determined by whether a higher verb selects it or not. I showed that the coordinator -ko or -ko3, which is a counterpart of and in English, is different from it in that the former is [+V] whereas the latter is [uV].
1. Introduction
2. -Ko: a Converb
3. -Ko as a Subordinator
4. -Ko as a Coordinator
5. Conclusion