Proto-Yenisseian: *ʔaj ( ~ x-)
Meaning: interrogative particle
Ket: aj 'why; what; how' (Castr. ʌj 'what')
Yug: aj 'why'
Comments: Werner 1, 18 (without reconstruction). One is also tempted to compare Ket ɛʔk / ɛk, Yug ɛk 'how, as; so as' (Werner 1, 228, 256) with a possible protoform *eʔx; the forms Ket, Yug aj in that case can be (with Ablaut) traced back to *ʔa(ʔ)x-i.