Bring out your kobolds
 

My rules for "Domestic kobolds" i.e. https://en.wikipedia.org/wiki/Kobold#House_spirits
Is that these are Goblins who have Common as their native tongue and either don't know the Goblin tongue or speak it with an accent. These are usually in the employ of some human (perhaps for many generations) and get a minus one to reaction rolls from "true goblins". Note that it is mostly other goblins who call them serfs of the humans or kobolds.

The only sure way of overcoming this status is to learn the Scholar talent.

Re: Bring out your kobolds
 

Perhaps they are small humanoids who move into and out of their houses through gates in the fireplaces. In which case the making of gates is a core ability. What they get out of living in human(oid)-occupied houses is also a question.