Where does “šū” come from?

šū (Proto-Afro-Asiatic) comes from Proto-Semitic *šuʔa — he (masculine third-person singular personal pronoun).

Ancestry of “šū”, step by step

StepLanguageWordMeaning
1Proto-Semitic*šuʔahe (masculine third-person singular personal pronoun)
Every word from Proto-Semitic *šuʔa