The participial oblique, a verb mood found only in Nunivak Central Alaskan Yup’ik and in Siberian Yupik

Montréal: l'Université de Montréal, Études/Inuit/Studies, Vol. 30 (1), 2006, p. 135-156.The PO mood does indeed seem like it has been "cobbled" together from the postbase -yagh-/-yar- and the participial mood with additional endings borrowed from those of the connective moods to accommodate 4th person, with a new "twist" put on the meaning of the aggregate of the parts. Finding the PO mood so similar in two widely separated areas, NUN CAY and CSY, in différent languages in fact, suggests that the PO mood in much its présent form goes back to proto-Yupik times. The dépendent use of the participial in GC Y discussed above with its limited set of endings, suggests that this "missing link" is a reduced offshoot from some earlier stage in the development of the PO mood.