Where does “יי” come from?

יי (Hebrew) comes from Hebrew יאהדונהי, from Hebrew יהוה, from Proto-Semitic *haway- — to be, to become, to fall, to happen.

Ancestry of “יי”, step by step

StepLanguageWordMeaning
1Hebrewיאהדונהי—
2HebrewיהוהYHWH, Yahweh, Jehovah; God; Yahweh
3Proto-Semitic*haway-to be, to become, to fall, to happen
Every word from Proto-Semitic *haway- →Every word from Hebrew יהוה →Every word from Hebrew יאהדונהי →