I will have to paraphrase this as I do not have a copy and cannot find an ebook version for sale - in Languages of the Night Ursula K. LeGuin was asked by some famous editor to do a talk / article about her research on Earthsea, show the maps, lexicon of the language and so forth to which she replied something like

"Dear famous Science Fiction editor,

While I know that this is the way many people write, it is not the way I do it. "

Her description of her process was that she made it up as she went along but because of her characters or locations there was always only one reasonable choice. So for example when Vivian is biting on Reginald's ankle he says "I do not think this is at all pertinent to the matter at hand", because, being Reginald what else could he possibly say? (anecdote about Reginald and Vivian from the article although no doubt mangled by the years between reading and now.