Comments: The root is used either independently (with the suffixed class marker -b) - mostly in the 3d (inanimate) class, but in Cham. and God. also in the 1st/2d classes - or in conjunction with another interrogative stem, *mV (see *ʔi-mV) - in the 1st/2d classes. Cham., Tind. and Kar. reflect also a stem *hidV- / *ʔidV- 'what' - but since there does not exist a class marker *-d, it is rather a quite different stem (see under *ʡǟdV 'thing; interrog. pronoun').
The most archaic form is Kar. (with *h-); other languages reflect the PA weakened variant, *ʔi-.