'냐/니' means same with '어/습니까/요' I wrote a letter to my friend last night. After a few days my friend ask me. "Did you write a letter?" 편지 썼어? 편지 썼냐? (It used between very close friends when they are student. If you graduate from school, don't use it) 편지 썼어? (It usded be friends or talk to a junior) 편지 썼니? (same with 썼어? but it has image of feminine expression ) 편지 썼어요? (talk to a stranger or superior) 편지 썼습니까? (formal) 2. I'm drawing a picture. Someone asks me "What are you drawing?" (무엇을 그리고 있습니까?) (friend) 무엇을 그리고 있니(있냐)(있어)? 3. I plan to trip this week. My friend ask me "What are you going to to this weekend?" (너는 이번 주말에 무엇을 할 거야(거니,거냐)?) 잖아 usually used for interjection and have intention of insistence to make sure. Interjiction. You ordered the steak but wrong dish is served. You can say yourself, 이 것은 (내가 주문했던 고기가) 아니잖아! (This is not steak!) and also you can talk to waiter "이 것은 내가 주문했던 고기가 아니잖아요!" 죠/지요 He is so cute, right? 그는 너무 귀여워요, 그렇죠? (그는 너무 귀엽죠?)

뭐하니/뭐하냐 What are you doing? People in regional provinces rarely use -니 since it sounds goody-goody. They use -냐 more often, so do I. I might use -니 when I'm upset(like "너 같으면 기분 좋겠니?") or I talk to a little kid. -잖아 is used to inform someone of something they're not aware of although they are supposed to be. 나 자고 있었어. I was sleeping. 나 자고 있었잖아. I was sleeping, wasn't I? (imlplies something like "Why did you wake me up?" or "So I didn't know you came in" etc, depending on the situation) Also, you can use -잖아 when you're upset. A : (watching TV) B : (stands before A, so A can't watch TV) A : 야, 비켜. 안 보이잖아. Hey, move over. I can't watch TV(Why are you standing there?). 안 보여 would be a nicer say of speaking, but if you're close friends, none of you will take offense at it. Though you could be screwed if your friend had a bad day. About 죠/지요, A₁: 그 강아지 귀여워요? Is the puppy cute? B₁: 아뇨. No. A₂: 그 강아지 귀엽죠? Is the puppy cute, isn't? (I think the puppy is cute and I'm sort of sure you think so.) B₂: 아뇨. No. A₂will be more disappointed. In assertive sentences, 죠/지(요) implies your attitude toward what you say. A : 안 졸려? Aren't you sleepy? B₁: 졸려. I am. B₂: 졸리지. I am. (and it's natural for me to feel sleepy)

Haha... you seem very curious in Koean.. that's good though :P You can just think of 냐/니? as a question form for your friends of the same age or younger Ex) 밥 먹었니/냐? (past), 얘가 네 친구니/냐?(present), 너 거기 갈거니/냐?(future) You can put polite forms instead of 니/냐? like 밥 먹었습니까?/먹었어요?/먹으셨어요?,etc.. 잖아 is like a tag question.. when you expect someone's answer or seek their agreement. Ex) 니가 너무 사랑했잖아? implies>>(아니야?/맞지?) the talker thinks it's true that they loved sb much. 너가 그랬잖아? you did that, (didn't you)? 내가 너보다 일 더 많이 하잖아? I work more than you! (아냐?/맞지?) 죠/지요 also used as similar as above 그 여자 너무 예쁘죠/지요? implies (isn't she?) >>we hardly use 지요, just say 죠 Not in questions, 당연히 내가 그랬죠. Of course I did that! 이 그림 누가 그린거니? 내가 그렸죠. Who drew this picture? I did. 밥 먹었어? 밥 먹었죠, 지금 시간이 몇 신데..Did you have a meal? Yes, of course. What time do you think it is now! >Answers are expected to be obvious, natural.. so that 죠 implies exclamation