Great episode!! Who would have thought that an episode centering on one of the less-popular main characters would have been so good? I think that's why I love this show.
I was sure that Jin spoke English but now I'm on the fence. The scene where Michael and Jin are fighting and it showed Jin listening to the others arguing -- it almost seemed like he didn't understand but was trying to learn. He may understand some but not near as well as Sun.
I think Jin has just turned hard from working with her father, just seems like there's no turning back for him......
I don't know if he's turned as hard as many of us think he has, or as hard as Sun may think. Yeah, he beat the crap out of that government official in front of his family and came home with his blood all over himself, but he kept the other guy from actually killing him. Jin may have done some things for Sun's father that he's not proud of, but is he a murderer? I have my doubts. The fact that he was going to stay in the US with Sun and start over, IMO, says he wasn't at the "no turning back" stage.
Even so, he probably feels extremely betrayed by Sun after learning that she speaks English. Even if he didn't understand what she said to him in the cave, he must realize why she learned English and what she was planning. That combined with her befriending Michael probably has him thinking he crossed that "no turning back" point long ago.
Next week's ep looks good. Shall we start a pool as to which character makes the first Indiana Jones reference??

I'll take Hurley in the first half hour.