I realize the tone dismatches original Chinese (all Chiense I know have Shang tone rather than Qu tone), and the form resembles Middle Chinese.
This "understand" could have come from "bright". tongyan, how do you use this word?
when i use the word 曉 in regular speech it is usually in a word-group like in 揭曉
i know the older generation uses 曉 to mean 'know, understand, familiar with'
i am sure most of the younger generation like me still understands the word in this context but will rarely use it, if ever. the only instance i can think of using it is to produce a comic effect, similar to the effect of using mandarin equivalents for cantonese terms.
let me illustrate its use in a hypothetical dialogue between me and my friend:
seeing that my friend has no idea how to use the computer i say:
me: 曉唔曉架你﹖ hiu ng hiu ga nei? (do you know how it's done, how it works, etc)
response: 曉你個死人頭 (literally, know ur D**n dead head)
ya know, like using 計程車 'gai sing ce' instead of 的士 'dik si' it's just used to induce laughter or irritate someone