Right, so I’ve posted my prologue. If you haven’t read it, I really hope you do sometime, because it’s a scene I really like. I always believe that in fantasy stories, or any work of fiction really, you should try to keep made up words to a minimum. I exempt names of individuals from this, unless they contain apostrophes, like Jor’tul or something. Any made up words you use should be introduced individually and spaced out over the entire work, so as not to overwhelm. Harry Potter is very good at this, except perhaps for the first chapter, and the “Yer a wizard, Harry” chapter. In my prologue, there are several funny names, but that’s about it. I mention the Magnolium Order without much explanation. Hopefully it’s clear that it’s a religious organization, and that’s all you need to know at the start.
That’s not to say you can’t have things unexplained. The true nature of that coin, for example, shouldn’t be revealed until much later in the story. Cardinal Alabaster is nowhere near as nice as 7-year old Romm thinks, and his motives will be expanded upon as the story progresses. And the king’s reason for killing that girl will be a major part of the plot; it will transpire that she did, in fact, have a son.
More important than not using confusing made-up words is not overloading the reader with an info dump, explaining all the reader has to know in a totally boring format. Again, Harry Potter was hit and miss at this. It was mostly good, except for the first few chapters of the first book, and the obligatory “Dumbledore Explains It All” chapter towards the end of each book. But by then, it was the end of the story, and we could stand some clearing up of mysteries. If you open with “Allow me to give you a history lesson about this fictional world of mine,” you will get very few readers.
I’m much worse with this than with not using made-up words. Interspersing plot with backstory is hard when there’s no good reason for the main character not to know the backstory. I just read a book that was actually quite good at this (Prospero Lost, by L. Jagi Lamplighter). It was written in first person, and the narrator knew everything she needed to about the backstory (though not about the current plot). So she didn’t discuss things she knew until they became relevant, or unless the character was reminded of that bit of history by something else that was going on. I think I should try to do that.