Seducing Mr. Perfect Mr. , alternatively known as Seducing Mr. Robin, is a South Korean film, released on December 7, 2006. It was written and directed by Sangwoo Kim and stars Uhm Junghwa as Min Joon and Daniel Henney as Robin Heiden.
One of the unique concepts of the movie is that Robin Heiden speaks only English because he finds Korean hard to speak, while Minjune speaks mostly in Korean. The two seem to understand each other perfectly without any outside translation. This was a new style of dialogue for Korean films, and it is partially credited for the films success.
Source: Wikipedia