INT 1 | ~거든요 VS ~잖아요

MEANING

~거든(요).	~잖아(요).
Assumes the listener doesn’t know the information	Assumes the listener knows this information
Explains new information, reason to “why?” question = more neutral to simply explain or answer	Telling a shared story or saying the listener should know already = it can sound rude
“You see”, “Let me explain”	“You know”, “You should know”

TIP: ~잖아(요) can sound rude unless you and the listener DEFINITELY share this information or story, so it is often used when people are arguing and fighting because of its meaning “you (should) know!”

CONJUGATION

EXAMPLE

친구: 왜 항상 이 식당만 와? (Why do you only come to this restaurant?)
나: 1) 여기 음식이 맛있거든. (You see, the food here is delicious.) – neutrally explaining “why”
2) 여기 음식이 맛있잖아. (You know the food here is delicious.) – Shared knowledge

친구: 어디 아파? 얼굴이 안 좋아. (Are you sick somewhere? You don’t look good.)
나: 1) 어제 잠을 못 잤거든. (You see, I couldn’t sleep well yesterday.) – neutrally explaining “why”
2) 어제 잠을 못 잤잖아. (You know I couldn’t sleep well yesterday.) – Shared knowledge

내가 말했잖아! 또 잊어버렸어? (You know I told you. Did you forget again?) – Shared experience

이게 아니잖아… 몇 번을 말해? (This isn’t it, you know. How many times am I telling you?)
– Assuming and insisting the other person must know because it was shared: sounds aggressive