I am truly glad to have cast you as Newgrounds' own Nene, I REALLY am. I caught this just by chance in my Audio feed, and not only are your expressions impeccable in both languages... your English is impeccable!

I only know a tiny, tiiiiiny bit of Korean so it didn't get me through all of this demo but I presumed that a lot of it had to do with the flow of what it was you were saying at any given point in time, e.g. the student chiding her classmate for dozing off in class. Amazing vocal clarity, at any rate -- and I'm looking forward to having you on board the project when the script is done!

Woah, you're good, especially on Korean. I don't get a thing (XD) but you sound more realistic, I guess... This doesn't mean English version is bad.
P.S. "Have you been sleeping in class?", though, not "Did you slept in class?") "You been sleeping in class?"(ommit "have") possibly to shorten the phrase and keep the emotion.
Oh, and does this mean you're the one who's gonna do the voice acting in that rsonbie456's animation(at least part of the job)?
Well, good luck anyway!

THIS IS AMAZING!!! So many expressions. It's pretty entertaining to listen!