The name that most people have the most trouble with -- Éireamhóine -- is not even one I invented, it's old Irish (though I did add an "e" at the end). I did think long and hard about whether I should change that one -- but what can I say? -- it just seemed to me that it really was his name. (All along, I halfway expected my editor to ask me to change it, but she never did.)
As a reader, I like characters that have names that seem consistent with their language and their culture, and over the years and books I've tried different approaches to achieve that goal.
In my first three books, the Green Lion books, the characters all had Celtic names. The trilogy was set in an imaginary extension of the British Isles, an island kingdom a little to the west of Ireland, so Welsh and Irish names only seemed appropriate. And some people did complain because the names were too hard, as though I ought to anglicize them, which I thought rather strange because they surely never would have done so had the story been set in a pseudo-Asian setting or an imaginary kingdom in the Middle East. At least I've never heard anyone suggest such a thing, and I really couldn't see why white-skinned characters couldn't get away with exotic multi-syllabic names too.
With my next set of books, the setting was similar to Europe and America in the 18th century, so that time easier and more familiar names seemed altogether appropriate. I'm still getting fan mail from people who love those books but -- I hate to introduce the commercial note, but facts are facts -- the books didn't do well enough at the time for my publisher to want more on the same lines, so I found myself under contract writing a series of direct sequels to the first trilogy instead.
With the second set of Celydonn books -- and a substantially new cast of characters -- I quickly ran out of even vaguely pronounceable Welsh and Irish names (or at least names that weren't already associated with famous characters), so I started throwing in Breton names and some of the more fanciful names of little known characters from the Arthurian mythos.
By the time I got around to writing the notorious "Queen's Necklace" I decided to be clever, giving the main characters names that were somewhat exotic but which reduced to familiar nicknames (Will and Lili), while most of the other characters had easy names like Luke, Sophie, Jarred, Rodaric, etc. And the book sold so poorly (yes, I'm still bitter, because I still think it was a wonderful story with wonderful characters) that it just about killed my career, and I was reduced to slinking about under cover of a pseudonym myself and imposing on the credulity of innocent booksellers.
After all this, I came to the conclusion that even though people like to complain (I like to complain when other writers use names that I think are ugly, or that seem inconsistent, or much too modern, or ... well, for a lot of different reasons, but that doesn't stop me from enjoying their books) generally speaking characters' names rarely impact the reader's experience of a book all that much. But they do matter, a great deal, to me as the writer -- I can't even write a character until I find a name that feels right to me. Besides, there is no way to come up with names that will please everybody, so why not go with the sure thing and please myself -- particularly as I'm the one who is going to have to live with them for months and years at a time?
And when I started writing "The Hidden Stars" I considered many, many different methods of coming up with appropriate names for people and places. I literally spent months poring through What-to-Name-Your-Baby books, maps, foreign-language dictionaries, mythology, ancient history -- at this point, I don't even remember all the different sources I used. And nothing felt right and nothing made sense until I decided to start experimenting with an invented language. Then I spent about a year constructing that language and putting together the elements to create lists of names. Even after I had done all that, and had names for most of my cast of characters, I still found the need for some "dialect" names, which sent me back to some of my original sources.
It was a lot of work -- an enormous amount of work -- and whether it was worth all that trouble I still don't know. Predictably, some readers have trouble with the names -- but then there are other readers who say that the names actually enhance the story for them. It may be years before the votes are all in and I can finally say for certain whether I made a wise choice or a huge mistake in doing things the way that I did.
(Still, the truth is, I was absolutely stalled and unable to proceed further until I decided to go with the invented language approach -- so there is a good chance that without these particular names the book might never have been written at all.
Many of you who will read this explanation write stories yourselves, and I am sure that you know that sometimes the creative process is ... mysterious, to say the very least.)