The proto-humans who were born telepathic in the lands of Altara. Where as Altaran is used to describe those progenitors who left their homeland and traveled to Arland and Ushra, Kith is used to describe their descendants who were only partially psionic.
See "Kith Language"
The Kith language still survives in many corners of the human lands. Many landmarks, parts of speech and word elements spoken in the various human languages owe their origin to the Kith.