SwiftKey is one of the most popular third party keyboard apps on the Google Android platform.
The company has just launched support for the Korean language through a beta app named SwiftKey Korean Beta.
SwiftKey said that this virtual keyboard app feature all the popular functionalities of their regular apps:
Dynamic learning of the words you use and how you use them
Personalization with Facebook, Twitter and Gmail for even better predictions and corrections
Input modeling (and heatmap visualization)
Ability to type in up to 3 languages at once
Easy switching between different keyboards (e.g. Korean and Qwerty)
They are offering it through the Google Android Market in Korea and through their own VIP Community section.