No one in Lubuagan before the arrival of the Americans ever heard or knew of the existence of Lumad tribes in Davao, or of other tribes beyond the border of their rival village or tribe as a whole.
The Tinguians are linguistically and culturally closer to Balbalan tribes than Isnegs of Abra.
Kalanguyas, from their very mouths attest their origin from Benguet, meaning they develop out of the Ibaloi group and did not come out off Indonesia. Like Tinguians, being an offshoot of Balbalan group.
(Bago tribe came from mixture of Ilocanos and Kankanays. Maranao tribe, an offshoot of Maguindanao tribe)
The tribe that was missed by our "historian", the Gaddangs cancelled all the integrity that is left of his Cordilllerian chronology.