Moonji can sing several Korean songs for kids almost 5 songs.
I am sorry you do not understand korean, but you can guess the sound and meaning when you watch the movie.
If I just say the subject of song, then he can sing a korean song successfully.
The subject of song is "A wild rabbit" and the words are ;
"San Toki Toki ya, Eo di rul ga nu nya ?" in Korean,
The meaning is "Dear rabbit rabbit, where are you going ?"
Have a nice day !!!