I just thought about a potential option from your question. We could also market from within SE as well! I went to search the Meta for any rules about this before I wrote them a note. Seems it is already being done.
Check this out!
Also, put the link to the proposal in your profile!!!
It may also be a good idea to scout English Language Learners. While not everyone is a native Korean speaker, some are going to this community for help with English.
Sorry if you all are already familiar with this but I am new and still becoming acclimated to SE.
Depending how invested in the idea you are, most universities have an international department. Some even have a language exchange department like The University of Texas @ Austin's PALS Program or The University of Washington @ Seattle's FIUTS Program are two examples.
Social websites such as Facebook have community groups and also a Facebook fan page promoting this community with class and style. Facebook is all about advertisement anyway.
There are a multitude of ways to market this!