Grammar Explanation: 못 vs. 수 없다
I want to explain to myself how to differentiate between these words because I say “I can’t speak Korean well” a lot, and i wanted to know the difference between these words, their meaning + nuisances. Please point out any errors!
these are mostly notes for me, but i hope it’s also helpful to anyone else who may find this. i’m still at a beginner level when it comes to korean learning, so i’m definitely not qualified to teach anything so pls lmk if anything is wrong and i’ll edit the post!
Saying “can’t” in Korean.
1. 못: Like the others, it translates to “can’t” in english, but it’s specifically used to stress that something cannot be done (specifically by the subject) because it is not possible given the circumstances. when using this, it only specifies that the subject can’t do *something* at the moment, not in general.
-ex: subject can’t do something because of an injury, personal reason…maybe not strong enough, etc.
-an adverb; can only be placed before a verb and not a noun. if a verb is a verb that contains a noun also, it’s placed in between.
난 공부 못 하다 = I can’t study
못 is placed in between the word 공부 (study/noun) and 하다 (to do/verb), however 공부하다 is one verb that means “to study”.
지 못하다 is just placed after an action verb stem. usually used in more formal situations.
also to stress that someone can’t do something because they’re bad at it. (can’t do something well)
Naver Dict. - (잘하지 못하다) be bad[poor] (at), be weak (in)
*note that 못하다 is one word unlike 못 하다
so, 못 하다 means one is unable to do something while 못하다 means that you’re bad at something.
2. (ㄹ/을)-수 없다: similar meaning to the 1st one. it is used in a situation to say that something is impossible due to certain circumstances for the subject. however, it’s especially used to stress that the subject can’t do something beyond their control.
you can remember this by breaking it down like this
ex: 나는 음식 없이는 살 수 없다. = i can’t live without food.
or basically, without food there is no ability/way to live.
-another way it differs from 못: 수 없다 will be used to stress a strong refusal to do something given the circumstances.
나는 내 전화기 없이 살 수 없다. = I can’t live without my phone.
Because of these differences, it may seem weird to use this form in certain situations. example:
I can’t speak Korean well:
because of the nature of 수 없다, it is weird to use it when saying that someone can’t speak Korean well, because it implies that speaking well is behind their control, or that it is impossible to do so.