From a recent conversation with Kerstin Hall:

“A lot of details are never seen by readers,” [Friedman] says. “Sometimes I come up with details that I intend to put into my books, but more often I develop ideas to flesh out my world and make it feel real, that never are directly relevant to the plot.”

For example…

“In the Dreamwalker series there are small hominids known as “abbies” that serves as slaves. I doubt my main characters will ever find out where that name is from, or who brought them to Terra Prime, or other details of the local slave market…but I need to know all that to keep the story consistent.”

“Characters have noted that the abbies have a strange, slightly awkward gait. It’s not an important story element, but it is because they were a hominid race snatched from their home world right at the time when they were evolving upright posture. All the evolutionary adjustments that the human foot underwent to support a permanent upright gait, they were still in the middle of.”

Read the full interview