Can someone be legally punished for using informal language?

Looking at the posts in the bullpen, someone mentioned that they have bad feelings toward a junior colleague who is younger than them but uses informal language (banmal).
Is there any legal provision that allows for punishment in this case?
Even if they are a senior, their job rank should be the same...
Conversely, if a younger subordinate uses informal language toward an older superior in a polite manner, is there no legal basis to punish them?