It becomes a moment of clarity when you change your entire fantasy world because no one can pronounce the words. A fantastical name is interesting until the point at which it throws the reader out because their brain is trying to figure out what it sounds like.
Though the original spellings are different, it's as close to the original pronunciation without the confusion, and allows a better flow when reading. Some pronunciation is explained only because I have a particular use of the letter "c", in which it is neither "s" nor "k", because those letters exist. This letter, in my writing, will always have a "ch" sound, because by itself it's a really illogical letter due to the others having the same purpose. Other names are explained in various parts of my works, as well, especially when confronted with other languages, but it's mostly phonetic.
Creation of new design, languages, cultures, and creatures is just euphoric.