Reconstruction:Proto-Japonic/su
Proto-Japonic
Etymology 2
Perhaps a native Japanese term, with the su reading somehow related to the way that very sour things cause one to pucker.
Alternatively, may be a prehistoric borrowing from Middle Chinese 醋 (MC tshuH), borrowed earlier than the systematic introduction of kanji (vinegar was historically introduced to Japan in the 300-400s from China), and then later mistaken as a native Japanese term. Compare modern Mandarin 醋 (cù) or Cantonese 醋 (cou3).
Descendants
Reconstruction
Deriving this verb from a stem *səy- has been proposed on the basis of an imperative *sə and the Japanese stem forms in se-, except that this contradicts the normal development of the diphthong -əy in Japanese, which should develop into /i/ instead of /e/.
In Japanese, the se- forms are mostly regular for the 下二段活用 (shimo nidan katsuyō, “lower bigrade conjugation”) pattern, raising the possibility that the above irregular phonetic development may instead be a regular conjugational shift.