The 'Vanishing' Siot (ㅅ Irregular Verbs)
ㅅ before vowels, but keep vowel-separation and treat the stem as if the consonant still exists.
Grammar Rule in 30 Seconds
When a verb stem ends in 'ㅅ' and meets a vowel-starting suffix, the 'ㅅ' disappears.
- If the stem ends in 'ㅅ' (e.g., 짓다), remove 'ㅅ' before a vowel: 짓 + 어 = 지어.
- If the suffix starts with a consonant (e.g., -고), keep the 'ㅅ': 짓 + 고 = 짓고.
- This rule only applies to specific verbs like 짓다 (to build), 낫다 (to recover), and 붓다 (to pour).
Overview
Ever felt like a word was playing hide-and-seek with you? In Korean, the ㅅ (siot) consonant is exactly that friend. It is there one moment and gone the next.
This happens with a specific group of verbs. We call them the ㅅ irregulars. Most of the time, ㅅ behaves perfectly.
But when it meets a suffix starting with a vowel, it vanishes. It doesn't leave a trace. This isn't just a random glitch.
It is a fundamental part of reaching the A2 level. Understanding this makes your Korean sound natural. If you say 나사요 instead of 나아요, people will still understand.
But you will sound like a textbook from the 1950s. We want you sounding modern and sharp. Think of the ㅅ as a shy guest at a party.
As soon as a vowel (the loud extrovert) walks in, the ㅅ slips out the back door. But it only happens with some verbs. Don't worry, I will show you which ones.
It is like knowing which friends are introverts. Once you learn the pattern, you will see it everywhere. You will see it in K-Dramas when someone recovers from a cold.
You will see it in cooking vlogs when someone stirs their dalgona coffee. It is a small rule with a big impact on your fluency. Let's get that ㅅ under control before it disappears again.
Conjugation Table
| Form | 짓다 (To build) |
낫다 (To recover) |
붓다 (To pour) |
|---|---|---|---|
| --- | --- | --- | --- |
| Stem | 짓 |
낫 |
붓 |
| Present (Informal Polite) | 지어요 |
나아요 |
부어요 |
| Past Tense | 지었어요 |
나았어요 |
부었어요 |
Future (-(으)ㄹ 거예요) |
지을 거예요 |
나을 거예요 |
부을 거예요 |
Connective (-(으)면) |
지으면 |
나으면 |
부으면 |
Honorific (-(으)세요) |
지으세요 |
나으세요 |
부으세요 |
How This Grammar Works
ㅅ consonant at the bottom of a verb stem (the batchim) is sensitive. It stays put when followed by a consonant.-고 or -지, the ㅅ is happy. For example, 짓고 (building and...) or 낫지 (recovering, right?). But vowels are the kryptonite for these specific ㅅ batchims.아, 어, 으, or any other vowel, the ㅅ drops out. However—and this is the trick—the verb still acts like the ㅅ used to be there. This means you still use the grammar rules meant for stems ending in a consonant.-으세요 instead of -세요. You use -은 instead of -ㄴ. It is like an invisible ghost of the ㅅ is still holding the spot.ㅅ was never there, 낫다 would become 나세요. But because the ghost of ㅅ exists, it becomes 나으세요. This "ghost rule" is what trips up most people.ㅅ is gone, but its influence remains. It is like a celebrity leaving a room; everyone is still talking about them. This applies to verbs like 짓다 (to build/make), 낫다 (to be better/recover), 붓다 (to pour/swell), and 젓다 (to stir).Formation Pattern
다. For 붓다 (to pour), the stem is 붓.
-어요, the answer is yes. If you are adding -고, the answer is no.
ㅅ. If the suffix starts with a vowel, delete the ㅅ. 붓 becomes 부.
부, the vowel is ㅜ. Following standard 아/어 rules, ㅜ takes 어. So we get 부어.
ㅜ + ㅓ becomes ㅝ. For example, 배우다 becomes 배워요. But for ㅅ irregulars, you do not contract. It stays as 부어요. This is vital!
부어 + 요 = 부어요.
Politeness Levels
Social context is everything in Korea. How you use these irregular verbs changes depending on who you are texting or talking to.
- **Formal/Business (-습니다)
** The ㅅ stays! Since -습니다 starts with a consonant, the rule doesn't trigger. Use 낫습니다 or 짓습니다 in a presentation or a formal interview. It sounds very professional and sturdy.
- **Informal Polite (-아요/어요)
** The ㅅ vanishes. This is your daily driver. Use 나아요 when telling your boss you feel better. Use 지어요 when talking about your new house on a Zoom call. It is friendly but respectful.
- **Casual/Banmal (-아/어)
** The ㅅ is gone here too. Use 나아 or 지어 with your best friends or younger siblings. If you are texting a friend about a cold, you'd say "이제 좀 나아?" (Are you feeling better now?).
- **Honorific (-(으)세요)
** The ㅅ drops, but you use the 으 version. 나으세요 is what you say to an older relative who is sick. It is the most polite way to wish someone a recovery. Pro tip: Don't use this for yourself. You can't be your own honorific unless you have a very high opinion of yourself!
When To Use It
- Health and Wellness:
낫다is the star here. Whether you are recovering from COVID or just a bad breakup, you are "getting better." Example: "감기가 다 나았어요" (My cold is completely gone). - Cooking and Dining:
붓다(to pour) and젓다(to stir) are essential for any foodie. If you are making a TikTok of your morning coffee, you커피를 저어요. If you are pouring soy sauce, you간장을 부어요. - Construction and Creation:
짓다isn't just for skyscrapers. You use it for이름을 짓다(making a name) or미소를 짓다(making a smile). If you are building a base in a game like Minecraft, you are집을 지어요. - Daily Annoyances:
붓다also means "to swell." If you ate spicy ramen at midnight and your face is puffy the next morning, you say "얼굴이 부었어요." - Writing and Planning:
긋다means to draw a line. If you are highlighting important parts in a textbook or drawing a line on a map for travel vlogging, this is your verb.
Common Mistakes
- 1Over-correcting: The biggest trap is thinking every verb ending in
ㅅis irregular. It is not! Verbs like웃다(to laugh),씻다(to wash), and벗다(to take off clothes) are REGULAR. They keep theirㅅ. If you say씨어요instead of씻어요, people will think you are trying to say something about seeds. Always double-check if the verb is on the "naughty list." - 2The Contraction Craze: We usually love shortening Korean words.
가아요becomes가요.주어요becomes줘요. But나아요never becomes나요.지어요never becomes져요. If you contract these, you change the meaning entirely.나요means "to appear" or "to happen."져요means "to lose" or "to set" (like the sun). Keep those vowels separate! - 3The Ghost Forgetfulness: Forgetting to use
으after theㅅdrops. Many learners say나면instead of나으면. Remember, theㅅwas a consonant. It leaves behind a "consonant-style" requirement. Think of it like a reserved seat at a concert. Even if the person leaves, the seat stays reserved.
Progressive Practice
Identify the Vibe: Look at these verbs: 씻다, 짓다, 벗다, 낫다. Which ones are irregular? (Answer: 짓다, 낫다).
Simple Conjugation: Take 젓다 (to stir). Add -어요. Step 1: 젓. Step 2: Drop ㅅ -> 저. Step 3: Add 어요 -> 저어요. Easy, right? Now try 웃다. Step 1: 웃. Step 2: It is regular! Keep the ㅅ. Step 3: Add 어요 -> 웃어요.
The Honorific Test: Try to make 낫다 polite for a teacher. 낫 -> 나 + 으세요 -> 나으세요. If you say 나세요, you are telling the teacher to "appear," which is just weird.
Real Sentence Building: Imagine you are at a café. You need to stir your latte. "라떼를 저어 주세요" (Please stir the latte).
The Final Boss: Combine it with past tense and a connector. "어제는 얼굴이 부었지만 오늘은 괜찮아요" (Yesterday my face was swollen, but today it is okay).
Quick FAQ
Is 있다 irregular?
No! 있다 is regular. You say 있어요. Never drop the ㅅ from 있다 or 없다.
How many ㅅ irregulars are there?
There aren't many. The main ones are 낫다, 짓다, 붓다, 젓다, 잇다, 긋다. Memorize these six and you are 95% of the way there.
Why doesn't 나아 contract to 나?
Because the language needs to distinguish it from the verb 나다 (to occur). If they both became 나, the world would be very confusing.
What about 씻다? It ends in ㅅ.
씻다 is regular. 씻어요. Think of it this way: you can't wash away the ㅅ from the word "wash."
Can I use 지어 for making food?
Only for rice! 밥을 지어요 is the set phrase. For other food, use 만들다 or 요리하다.
Is this rule used in texting?
All the time. If a friend is sick, you text "빨리 나아!" (Get well soon!). It is super common in KakaoTalk.
Conjugation of 짓다 (to build)
| Form | Suffix | Result |
|---|---|---|
|
Polite (Present)
|
-어요
|
지어요
|
|
Polite (Past)
|
-었어요
|
지었어요
|
|
Formal (Present)
|
-습니다
|
짓습니다
|
|
Connective
|
-고
|
짓고
|
|
Connective
|
-지만
|
짓지만
|
|
Conditional
|
-으면
|
지으면
|
Meanings
The 'ㅅ' irregular rule describes a specific group of verbs where the final consonant 'ㅅ' is deleted when followed by a vowel-initial suffix.
Irregular Deletion
The deletion of the final 'ㅅ' in specific verb stems before vowel-initial endings.
“밥을 짓다 -> 밥을 지어요”
“병이 낫다 -> 병이 나았어요”
Reference Table
| Form | Structure | Example |
|---|---|---|
|
Affirmative
|
Stem + Vowel
|
지어요
|
|
Negative
|
안 + Stem + Vowel
|
안 지어요
|
|
Interrogative
|
Stem + Vowel + -요?
|
지어요?
|
|
Past
|
Stem + 았/었
|
지었어요
|
|
Future
|
Stem + ㄹ 거예요
|
지을 거예요
|
|
Connective
|
Stem + 고
|
짓고
|
Formality Spectrum
밥을 짓습니다. (Daily life)
밥을 지어요. (Daily life)
밥을 지어. (Daily life)
밥 지어. (Daily life)
The Vanishing Siot
Vowel Suffix
- 지어요 build + polite
Consonant Suffix
- 짓고 build + and
Examples by Level
밥을 지어요.
I cook rice.
병이 나았어요.
The illness recovered.
물을 부어요.
I pour water.
집을 지어요.
I build a house.
감기가 다 나았어요.
My cold has completely recovered.
맛있는 밥을 지어요.
I am cooking delicious rice.
컵에 물을 부었어요.
I poured water into the cup.
그는 시를 지어요.
He writes poems.
상처가 다 나아서 다행이에요.
I'm glad the wound has healed.
어머니께서 밥을 지으셨어요.
My mother cooked rice.
뜨거운 물을 부으면 안 돼요.
You shouldn't pour hot water.
새로운 계획을 지어 봅시다.
Let's build a new plan.
그는 병이 나은 후에 여행을 갔습니다.
He went on a trip after he recovered from his illness.
정성껏 밥을 지어 대접했습니다.
I cooked rice with care and served it.
기름을 부어 튀기세요.
Pour oil and fry it.
그는 거짓말을 지어냈어요.
He made up a lie.
병이 나을 기미가 보이지 않습니다.
There is no sign of the illness recovering.
그는 훌륭한 건축물을 지어 올렸습니다.
He built a magnificent building.
물을 붓는 양을 조절하세요.
Adjust the amount of water you pour.
그는 시를 지어 낭독했습니다.
He wrote a poem and recited it.
그는 병이 나은 듯 보였으나 다시 악화되었습니다.
He seemed to have recovered, but it worsened again.
그는 새로운 이론을 지어내어 학계를 놀라게 했습니다.
He fabricated a new theory and shocked the academic world.
물을 부어 반죽을 완성하십시오.
Pour water and complete the dough.
그는 고통을 딛고 다시 일어섰습니다.
He overcame the pain and stood up again.
Easily Confused
Learners think all 'ㅅ' verbs are irregular.
Both involve consonant changes before vowels.
Both involve stem changes before vowels.
Common Mistakes
짓어요
지어요
웃어요 (regular)
웃어요
낫어요
나았어요
붓어요
부어요
짓고 -> 지고
짓고
낫다 -> 나다
낫다
붓어서
부어서
짓으세요
지으세요
낫으니까
나으니까
붓을 거예요
부을 거예요
짓어내다
지어내다
낫어지다
나아지다
붓어버리다
부어버리다
Sentence Patterns
감기가 다 ___.
맛있는 밥을 ___.
컵에 물을 ___.
그는 시를 ___.
Real World Usage
감기 다 나았어?
물을 부으세요.
계획을 지었습니다.
맛있는 밥을 지어 먹었어요.
시를 지어 봤어요.
육수를 부어 드세요.
Memorize the Big Three
Check the Suffix
Use Context
Respect the Language
Smart Tips
Check if it's on the irregular list.
If it's irregular, drop the 'ㅅ'.
Keep the 'ㅅ'.
Drop the 'ㅅ'.
Pronunciation
Consonant preservation
When 'ㅅ' is followed by a consonant, it is pronounced as a 't' sound.
Vowel deletion
When 'ㅅ' is deleted, the syllable becomes open.
Statement
지어요. ↘
Falling intonation for a standard statement.
Memorize It
Mnemonic
The 'ㅅ' is a shy ghost; it vanishes when it sees a vowel.
Visual Association
Imagine a letter 'ㅅ' wearing a cloak. When a vowel comes near, it pulls the cloak over its head and disappears.
Rhyme
When the vowel comes to play, the 'ㅅ' runs far away.
Story
The letter 'ㅅ' was very shy. One day, it met a vowel and got so nervous that it vanished. Now, whenever a vowel approaches, the 'ㅅ' hides, but it stays brave and visible when it meets a consonant.
Word Web
Challenge
Write 5 sentences using '짓다', '낫다', and '붓다' in both past and present tense.
Cultural Notes
Cooking rice (밥을 짓다) is a culturally significant act, often associated with home and care.
Recovering from illness (병이 낫다) is a common topic of polite inquiry.
Pouring (붓다) is used in many traditional recipes, like pouring broth.
The 'ㅅ' irregular rule stems from historical phonological changes in Middle Korean.
Conversation Starters
요즘 감기가 다 나았어요?
오늘 저녁에 밥을 지을 거예요?
컵에 물을 부어 줄래요?
시를 지어 본 적 있어요?
Journal Prompts
Common Mistakes
Test Yourself
짓다 + 어요
감기가 다 ___.
Find and fix the mistake:
물을 붓어요.
짓다 + 고
낫다
Match each item on the left with its pair on the right:
All verbs ending in 'ㅅ' are irregular.
A: 감기 어때요? B: ___.
Score: /8
Practice Exercises
8 exercises짓다 + 어요
감기가 다 ___.
Find and fix the mistake:
물을 붓어요.
짓다 + 고
낫다
짓다
All verbs ending in 'ㅅ' are irregular.
A: 감기 어때요? B: ___.
Score: /8
Practice Bank
10 exercises컵에 물을 _____. (Present tense, informal polite)
차를 / 저었어요 / 제가
Identify the regular verb.
Are you feeling better?
Match these pairs.
얼굴이 붰어요.
빨리 _____.
고양이 / 이름을 / 지어 / 줬어요
낫다 + -고
Stir the soup.
Score: /10
FAQ (8)
No, only a few like 짓다, 낫다, and 붓다. Most are regular.
It's a historical sound change that became a rule.
Yes, it happens in all speech levels.
The 'ㅅ' stays. For example, 짓고.
No, 씻다 is regular. It is 씻어요.
Practice and memorization. Use them in sentences.
Yes, it is standard Korean.
No, it's just a spelling and pronunciation change.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Verbo irregular
Spanish changes the vowel; Korean deletes the consonant.
Verbe irrégulier
French uses elision; Korean uses deletion.
Starke Verben
German changes the vowel; Korean deletes the consonant.
Fukisoku doushi
Japanese irregulars are fewer in number.
Fi'l mu'tall
Arabic changes the root letter; Korean deletes it.
None
Chinese verbs never change form.
Learning Path
Prerequisites
Learn These First
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