I remember reading, in the 80s, an English-language teen-SF novel involving two teen protagonists (1 male, 1 female) on a planet (not Earth) that might have had some history of slavery (or inter-caste strife) and had dragons. Almost every character had a double KK in their name, though that might have been a caste marker.
That's literally all I remember, except that the author might have been female. (My head keeps suggesting Marion Zimmer Bradley, but I'm pretty sure it's not her.) If I read it in the 1980s, it was almost certainly written in the 1970s or 1980s.