선영 taught me what is ㅎㅎ, ㅋㅋ, ㅜㅜ and ㅠㅠ. Today, I came across more common Korean slang from KOREAN BLOG. So excited ^^ Here's the list obtained from Korean Language Blog
Means : hahaha
Means : kkk (noise of laughter)
Means : short for 응, which is an informal way to say “yes”.
Means : "No, No". The Hangul letter ㄴ makes an “n” sound and so this letter is used to represent a shorter way of saying the word “no”, which begins with an “n” sound as well.
Means : "Hi". It comes from the word 하이, where the first letter from each syllable is used to make ㅎㅇ.
Means : "Bye”. It comes from the word 바이.
Also means “bye”. The Hangul letter ㅂ begins with a “b” sound and so does the word “bye”. Hence that’s why ㅂ is used. The second part of this contracted word is the numeral 2, which in Sino-Korean numbers is pronounced as 이.
Means "Okay". The ㅇ part of the ㅇㅋ looks like the English letter “o” and the letter ㅋ represents the “k” sound in okay.
(9) ㅜㅜ or ㅠㅠ
Indicates crying or tears. The horizontal line in that looks like this ㅡ in ㅜ or ㅠ symbolizes the person’s face. The vertical line(s) are the tears streaming down the person’s face.
Means : "Disappointment" or "Discouragement". The ㅇ is the person’s head and ㅜ is the person’s body. The ㄴ is the person’s knees on the floor. All together it represents someone with their hands and knees on the floor in frustration or disappointment.