Where does “所謂” come from?

所謂 (Japanese) comes from Japanese 言う, from Proto-Japonic ipu.

Ancestry of “所謂”, step by step

所謂 traces back through two separate lines of ancestry.

via Japanese 言う

StepLanguageWordMeaning
1Japanese言うto say, to tell somebody; to call, to name, to...
2Proto-Japonicipu

via Chinese 所謂

StepLanguageWordMeaning
1Chinese所謂so-called; what is known as
Every word from Proto-Japonic ipuEvery word from Japanese 言う