Is there a way to change the unit responses from English to say....Korean? The Korean voices just sound honestly way better.
According to this official site, setting your language "pack" can be done in-game. The fact that they refer to it as a "pack" probably means that changing only the in-game voices is non-trivial.
Looking at this teamliquid thread, this guy seems to have had success changing his sound to korean.
Edit: Reddit page with instructions here