The process of how a K-Pop song is made is quite interesting if you really know how it is done.
Often times, K-Pop entertainment agencies would get in contact with songwriters in both domestic and overseas markets. And things get especially interesting if it is from the latter, as a large portion of songs written by foreign songwriters were usually intended for US pop stars. In fact, the demos are all cut in English, and later changed into Korean once a K-Pop agency confirms the purchase of a song. This of course, is completely different than remakes since demos are songs that haven't been released, but have ended up with idol groups whereas the former is when an idol group buys the rights to an existing song and re-release it.
Below are a few K-Pop idol group songs in their original demo format.
f(x) - 4 Walls
EXO - Call Me Baby
Girls' Generation - You Think
f(x) - Pink Tape 10 (No More)