Norman and Mei (1976), Schuessler (2007), Sagart (2008): Related to Min Chinese 捌 (“to know”) (proto-Min: *pat). The direction of borrowing is debated; Norman and Mei, and Schuessler favour an Austroasiatic origin for this word, and regard Min as a loan. Sagart, on the other hand, proposes that the sense “to know; to recognise” in both Min and Vietnamese is an extension of the sense “to differentiate; to separate” of 別 (), and hence treats V. biết as a *pred, *brednon-Sino-Vietnamese reading of Chinese 別 (SV: biệt), a semantic development shared with Min.
- to know; to realize; to understand
- 1936, Vũ, Trọng Phụng, Số đỏ [Dumb Luck] (in Vietnamese):
- Cụ Hồng lại nhăn mặt lần thứ mười mà khẽ gắt cũng lần thứ mười rằng:
— Biết rồi ! Biết rồi ! Khổ lắm, nói mãi !
- Great-granddad Hồng groans for the 10th time as he grimaces also for the 10th time: "Oh I get it! I get it! Enough with the nagging already!"