You've created your world. You've brought a supernatural being onto the page. And sometimes they require their own language. A few words here and there. Curses, exclamations, incantations... Those words they'd fall back on when English just doesn't do them justice.
For the most part, I enjoy creating words in my being's native tongue. But sometimes, it takes a while for just the right letter and vowel combinations to come together. It's got to sound right. It's got to read right. You know?
How do I find 'new' words?
Um, I read things backwards. I've done this since I was a child. Specifically, I read road signs backwards (after, of course, I read them properly otherwise I'b be lost all the time). Towns, cities, road names, whatever is out there. The ones I see on my regular journeys, I bypass b/c, you know, I've already read them. Sometimes, all it takes is a change of one letter or vowel. I've come up with some cool, 'off-world' sounding words by doing this.
This weird childhood travelling pastime has led to me randomly reading things backwards. A word flashed on the TV, a word on the cover of a book, menus, whatever strikes me. . . (For instance, yesterday I spelled the word 'gulp' backwards in my head after the Hub used the word, and I realized it spelled 'plug'. I love it when that happens!).
Other things I've done is going through foreign language dictionaries, name databases, and my latest kick -- those verification codes you have to enter in blogger and other online forms. Yeah. Loads of possibilities there. :D