In a previous article, we explained the basic way to do negation in Korean using the form -지 않다 and its short-form 안. There is another more specific form of negation which uses the verb 못하다, which is -지 못하다 and its shortened form 못. This negative expression in Korean focuses on a whole different kind of negation than -지 않다. Let’s take a look.
The negative form using -지 못하다 and its short-form 못하다 is very similar in meaning and use to -(으)ㄹ 수 없다. Besides just negating whatever the speaker is conveying, this form also indicates the reason as to why. It indicates that whatever is said is either beyond the capabilities of the speaker, an impossibility due to other factors. Thus the major focus is the lack of ability which is the same when you use the form -(으)ㄹ 수 없다.
Like -지 않다, -지 못하다 has a short-form, 못. The rules of using this form are very similar to 안. However, when you use it with a 하다 verb, do keep in mind that the spelling ends up a bit different. As mentioned earlier this grammar form is based on the Korean verb 못하다, which itself, as you can notice, is a 하다 verb, so when you use the short form with 하다 verbs, you actually use the verb 못하다 itself and thus you need to write it in one word. The noun part of the 하다 verb you want to negate is used as the object of the sentence indicated at times with the object particle -을/를. Keep this in mind.
가: 다음 주에 같이 수영할래요?
나: 음…저는 수영을 못해요.
A: Shall we go swimming next week?
B: Um… I can’t swim.
How To Use
Using the form -지 못하다 and its short form 못 are very easy to use. When you use the long-form, -지 못하다, you simply need to attach it to the verb stem of the verb you want to negate. When you use the short-form 못, you simply write it in front of the verb you want to negate. However, with the short-form do keep an eye out for the 하다 verbs, because you need to then write it in one word and put the noun part of the 하다 you are negating in front as the object of the sentence.
Lastly, due to the nature of this negation, which expresses an impossibility to do something, you can only use it with verbs normally. Adjectives generally don’t use this type of negation. However, after they have become verbs using patters like -아/어지다. Keep this in mind.