There is a guest at work who keeps mispronouncing words, however I am not going to correct them.
Why are you not going to correct them?
They are mispronouncing every other word.
It's fine if it makes them uncomfortable. They will eventually learn the right way to pronounce things.
I'm going to move on to bigger problems.
Moving on seems like the right thing to do. While correcting someone every now and then, doing so repeatedly is rude and might embarrass them.