Okay kiddo, a Korean ballad is a type of song that usually tells a really sad story. It's kind of like when you read a sad book or watch a sad movie and the characters are going through a tough time. They might be missing somebody they love, or they might be feeling really lonely.
Korean ballads are usually sung by one person and the music is usually slow and sad. Sometimes there are a lot of very emotional words and they are sung with a really pretty voice. The words usually make you feel like you want to cry because they are so sad.
People really love Korean ballads because they feel the emotions in the song and it's like they can feel what the singer is feeling. It's a little bit like when you watch a really good magic show and you get excited because you don't know how the magician did the trick. You just know that you really enjoyed it.
So, that's what a Korean ballad is. It's a very sad song that makes you feel like you want to cry, but people really love it because they can feel the singer's emotions, just like in a good magic show.