Where does “־יקייט” come from?

־יקייט (Yiddish) comes from Yiddish ־קייט, from Yiddish ־יק, from Middle High German -ec, from Old High German -ig, from Proto-West Germanic -g, from Proto-Germanic -gaz, from Proto-Indo-European -ḱos — -y, -ic.

Ancestry of “־יקייט”, step by step

Step	Language	Word	Meaning
1	Yiddish	־קייט	-ness; -ity; -hood; -ship
2	Yiddish	־יק	-y, -ic
3	Middle High German	-ec	—
4	Old High German	-ig	—
5	Proto-West Germanic	-g	Forms adjectives from nouns and verbs with a...
6	Proto-Germanic	-gaz	-y
7	Proto-Indo-European	-ḱos	-y, -ic

Every word from Proto-Indo-European -ḱos →Every word from Proto-Germanic -gaz →Every word from Proto-West Germanic -g →