Where does “Y” come from?

Y (Middle Persian) comes from English hyah, from Proto-Indo-Aryan Hyás, from Indo-Iranian *Hyás, from Proto-Indo-European Hyós — who, which; already.

Ancestry of “Y”, step by step

StepLanguageWordMeaning
1Englishhyaha call, often to horses, livestock, or cattle, to...
2Proto-Indo-AryanHyás—
3Indo-Iranian*Hyás—
4Proto-Indo-EuropeanHyóswho, which; already

Words derived from “Y”

Every word from Proto-Indo-European Hyós →Every word from Indo-Iranian *Hyás →Every word from Proto-Indo-Aryan Hyás →