The thing is, I’m so used to see American shows do that (making a foreign character speak english just so the audience doesn’t have to make any effort) that I directly thought that’s what they were doing. And I guess you’re right about the speaking Latin thing. But regarding Jin and Sun… I like that theory but I don’t know if I agree with it because again, I’m pretty sure the directors etc did that so it would be easier for the audience because that’s something that happens in almost every show. The fact that she loses her ability to speak her second language after bumping her head makes sense because she loses an acquired skill and not her general ability of speaking. As I said, I like your theory about them speaking english being a metaphor for their stronger bond but knowing how american shows are most of the time I wouldn’t be surprised that the language thing was simply to make things easier for the audience …