In the introduction to the present volume (p. 236) I have expressed the opinion that the Tinguian and Ilocano are identical, and that they form one of the waves of a series which brought the Apayao and western Kalinga to northern Luzon, a wave which reached the Islands at a later period than that represented by the Igorot, and which originated in a somewhat different region of southeastern Asia. [26]

In order to come to a definite decision concerning these various theories, we shall inquire into the cultural, linguistic, and physical types of the people concerned.

The most striking cultural differences between the Igorot and the Tinguian, indicated in the introduction, will be brought out in more detail in the following pages, as will also the evidence of Chinese influence in this region.  Here it needs only to be restated, that there are radical differences in social organization, government, house-building, and the like, between the Igorot-Ifugao groups, and the Ilocano-Tinguian-Apayao-Kalinga divisions.

All the tribes of northwestern Luzon belong to the same linguistic stock which, in turn, is closely related to the other Philippine languages.  There are local differences sufficiently great to make it impossible for people to communicate when first brought together, but the vocabularies are sufficiently alike, and the morphology of the dialects is so similar that it is the task of only a short time for a person conversant with one idiom to acquire a speaking and understanding knowledge of any other in this region.  It is important to note that these dialects belong to the Philippine group, and there seems to be very little evidence of Chinese influence [27] either in structure or vocabulary. [28]

The various descriptions of the physical types have been of such a conflicting nature that it seems best at this point to present rather detailed descriptions of the Tinguian, Ilocano, and Apayao, and to compare these with the principal measurements of the other tribes and peoples under discussion.

For purposes of comparison, the Tinguian have been divided into a valley and mountain group; for, as already indicated, there has been a considerable movement of the mixed Kalinga-Igorot people of the upper Saltan (Malokbot) river, of Guinaan Lubuagan and Balatok, into the mountain districts of Abra, and these immigrants becoming merged into the population have modified the physical type to a certain extent.

In the detailed description of the Ilocano, all the subjects have been drawn from the cities of Bangued in Abra, and Vigan in Ilocos Sur, in order to eliminate, so far as possible, the results of recent intermixture with the Tinguian,—­a process which is continually taking place in all the border towns.  The more general tabulation includes Ilocano from all the northern provinces.

Aged and immature individuals have been eliminated from all the descriptions here presented. [29]