This book is an older one, because I know I read it at least 10 years ago, and I seem to remember that it wasn't a new book.
Here's what I can recall...
Humans have figured out how to build teleportation devices. They go to colonize a planet..and find an "indigenous" species of cat-like people. Well, as the story goes on, you find out that the cat-people also have traveled to the planet and have advanced technology like teleportation devices.
There's a little boy in the story, and somehow he ends up with the cat-people instead of his own family. He wears a rope tail and ends up being in charge of translating the talks between the two races.
Anyone have a clue?
"Lurk! Withdraw! Upon them! this is the Law of the Battle of Conquest "
-Liber AL III:9