📘 Grammar 53: How to Use ~지 못하다 vs 못 – Expressing Inability in Korean

📘 How to Use ~지 못하다 vs 못 – Expressing Inability in Korean

Do you want to say “I can’t go,” “I couldn’t sleep,” or “I’m not able to speak Korean well” in Korean?

Then you should learn the difference between 못 and ~지 못하다, the two main ways to express inability or failure to do something in Korean.

Though they mean similar things, they differ in nuance, formality, and usage.

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📌 What Do 못 and ~지 못하다 Mean?

• 못 + verb: can’t, unable to (casual and spoken)
• ~지 못하다: cannot, unable to (more formal or written)

Both expressions are negative and indicate inability or failure, but the way they’re built and used is slightly different.

Structure:

• 못 + verb (placed directly before the verb)
• Verb stem + 지 못하다 (conjugated like any verb)

📘 Example Sentences

• 못 가요 – I can’t go
  mot ga-yo
• 가지 못해요 – I cannot go
  ga-ji mot-hae-yo
• 못 봤어요 – I couldn’t see
  mot bwat-seo-yo
• 보지 못했어요 – I wasn’t able to see
  bo-ji mot-haet-seo-yo
• 한국어를 잘 못 해요 – I can’t speak Korean well
  han-guk-eo-reul jal mot hae-yo
• 한국어를 잘 하지 못해요 – I am not able to do Korean well (formal)
  han-guk-eo-reul jal ha-ji mot-hae-yo

📊 Grammar Table – 못 vs ~지 못하다

Expression	Example	Meaning	Romanization
못 가요	못 가요	I can’t go	mot ga-yo
~지 못하다	가지 못해요	I cannot go	ga-ji mot-hae-yo
못 먹어요	못 먹어요	I can’t eat	mot meo-geo-yo
~지 못하다	먹지 못해요	I cannot eat	meok-ji mot-hae-yo

💡 Nuance & Usage Differences

• 못: more natural in everyday conversation, sounds emotional and immediate
• ~지 못하다: sounds polite, formal, and is often used in writing or speeches

Example:

• 못 했어요 – I didn’t manage to do it (casual)
• 하지 못했어요 – I was unable to do it (polite/formal)

💬 Most Koreans use 못 in casual speech, and ~지 못하다 in more official or respectful contexts.

❗ Common Mistakes

• ❌ 지 못 가요 → ✅ 못 가요 or 가지 못해요
• ❌ 못하다 + verb → Incorrect unless the verb is compound (e.g. 공부하다)
• Use 못하다 only with compound action verbs like 공부하다, 요리하다

🧪 Mini Quiz – Test Yourself!

1. How do you say “I can’t see”?
   a) 보지 못해요
   b) 못 봐요
   
   Click to Show Answer

   ✅ Both are correct! a) is more formal, b) is more casual

2. Translate: “I couldn’t go because I was sick.”
   a) 아파서 못 갔어요
   b) 아파서 가지 못했어요
   
   Click to Show Answer

   ✅ Both a) and b) are acceptable

3. Which is better for a business email?
   a) 못 했습니다
   b) 하지 못했습니다
   
   Click to Show Answer

   ✅ b) 하지 못했습니다 (more formal and appropriate)

✅ Conclusion

Now you understand how to use both 못 and ~지 못하다 to express inability in Korean!

• ✔️ Use 못 in casual conversations
• ✔️ Use ~지 못하다 in formal settings or writing
• ✔️ Both mean “cannot” or “unable to,” but have different nuance

Practice these:

• “I can’t come today” → 오늘 못 와요 / 오늘 오지 못해요
• “I couldn’t sleep well” → 잘 못 잤어요 / 잘 자지 못했어요

📘 Coming Up Next

Next lesson: How to Use ~지 마세요 – Telling Someone Not to Do Something
Learn how to say “Don’t go,” “Please don’t eat that,” and more!

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