1. (As) You know...
You can use this attitude ending to say something the listener already knows or to remind them of something they have forgotten. Just like every attitude ending, it is only reserved for casual conversation. Pretty straightforward if you pay attention to what it’s called: attitude ending. In most formal situations, you wouldn't want to sound like you’ve got an attitude, would you? Basically, think of this ending as “(as) you know…” in English. Let’s take a look at some example sentences put together again with my imagination.
아내: “당신, 오늘도 집에 안들어와요?”
남편: “오늘 회사 사람들이랑 술 마시잖아”
Wife: “honey, are you not coming home today either?” (Ooooops!)
Husband: “You know, I am having drinks with my colleagues today.”
2. When Telling Someone off
You can also use this ending to tell someone off by quoting your own advice or warning given before to prevent things from going south.
친구: “아 어제 너무 달렸더니 속이 아프다. 토하고 싶어”
친구: “내가 천천히 마시라고 했잖아.”
Friend: “My stomach hurts since I drank a lot yesterday. I want to throw up”
Friend: “I told you to take it slow.”
Here is the formula you can remember in case you decide to add some more variety to how your verb comes off. I know most beginners are familiar with the informal polite speech ending like 아/어요. When the underlying situation is that the listener already knows what you are about to say, then conjugate the verb using this formula. You will sound more natural!
Present Tense: -잖아요.
Past Tense: -았/었잖아요
Future Tense: -(으)ㄹ거잖아요.
You could also use “있잖아요” as a conversation starter to mean “guess what”.
“있잖아요. 나 등이 간지러워요. 긁어 줄 수 있어요?”
“Guess what, my back’s itchy. Can you scratch it?”
Again, this ending is to be used in informal situation as it can sound rude to your superior. I will pump out more articles for you later on! much love mwah