The Disappearing 'S': ㅅ Irregular Verbs (ㅅ 불규칙)
Grammar Rule in 30 Seconds
When a verb stem ends in 'ㅅ' and meets a vowel, the 'ㅅ' drops out completely.
- Identify stems ending in 'ㅅ' (e.g., 짓다, 낫다).
- When adding a vowel-starting ending (e.g., -아요, -어서), drop the 'ㅅ'.
- If the ending starts with a consonant (e.g., -고, -지만), keep the 'ㅅ'.
Overview
The ㅅ irregular conjugation (ㅅ 불규칙, _siot bulgyuchik_) is a fundamental phonetic rule in Korean that affects a specific group of verbs and adjectives ending in the consonant ㅅ in their stem. This irregularity dictates that the final ㅅ of the verb stem disappears when it is immediately followed by a vowel-initial suffix. This phonological change ensures smoother pronunciation, a common principle underlying many Korean irregular conjugations.
Mastering this rule is crucial for producing natural-sounding Korean, moving beyond mechanical textbook application.
This irregularity does not apply to all verbs ending in ㅅ. A subset of ㅅ-final verbs remain regular, meaning their ㅅ is retained regardless of the following suffix. Distinguishing between these irregular and regular ㅅ verbs is a key learning objective.
The pattern consistently appears across various politeness levels and tense conjugations, making its understanding broadly applicable. The retention of the implicit "consonant stem" status for purposes like -(으)면 is a critical nuance often overlooked by learners.
Conjugation Table
| Verb Stem | Dictionary Form | Meaning | Present Polite (-아요/어요) | Present Casual (-아/어) | Past Polite (-았어요/었어요) | Formal Polite (-ㅂ니다/습니다) | Connective (-으면/면) | Purpose (-으러/러) | ||
|---|---|---|---|---|---|---|---|---|---|---|
| :-------- | :-------------- | :-------------- | :--------------------------- | :-------------------- | :--------------------------- | :---------------------------- | :------------------ | :---------------- | ||
| 낫- | 낫다 |
to recover | 나아요 |
나아 |
나았어요 |
낫습니다 |
나으면 |
나으러 |
||
| 짓- | 짓다 |
to build/make | 지어요 |
지어 |
지었어요 |
짓습니다 |
지으면 |
지으러 |
||
| 젓- | 젓다 |
to stir | 저어요 |
저어 |
저었어요 |
젓습니다 |
저으면 |
저으러 |
||
| 붓- | 붓다 |
to pour/swell | 부어요 |
부어 |
부었어요 |
붓습니다 |
부으면 |
부으러 |
||
| 잇- | 잇다 |
to connect | 이어요 |
이어 |
이었어요 |
잇습니다 |
이으면 |
이어러 |
How This Grammar Works
ㅅ irregular pattern is primarily a phonetic phenomenon designed to facilitate smoother pronunciation. In Korean phonology, sequences of certain consonants followed by vowels can be phonetically awkward or create a hiatus. The deletion of ㅅ before a vowel-initial suffix resolves this, allowing the preceding vowel sound to flow directly into the vowel of the suffix.낫 + -아요 as 나사요 would require an extra syllable or a jarring break; 나아요 flows more naturally.ㅅ leaves a phonological trace that influences subsequent grammatical choices. Specifically, when attaching suffixes that differentiate between vowel-final and consonant-final stems (e.g., -(으)면 vs. -면, -(으)러 vs.-러, -(으)세요 vs. -세요), irregular ㅅ verbs behave as if the ㅅ were still present. This means you must use the form appropriate for consonant-final stems, even though the ㅅ has been deleted.낫다 (stem 낫-) becomes 나으면 with -(으)면, not 나면, because the original stem ended in a consonant.나으세요 (please recover) where -(으)세요 is attached, but 나아요 (is better) where the ㅅ is simply dropped before -아요.ㅏ in 낫-, ㅣ in 짓-, ㅓ in 젓-, ㅜ in 붓-) determines the choice of -아/어요 suffix, precisely as it would for any regular verb stem.Formation Pattern
ㅅ irregular verbs involves a specific, sequential process. You must first identify if the verb is indeed irregular, then apply the deletion rule, and finally attach the appropriate suffix, mindful of the "ghost consonant" effect for certain grammar points.
다 from the dictionary form. For 낫다, the stem is 낫-. For 짓다, it is 짓-.
-아/어요, -았/었어요, -(으)면, -(으)세요, -(으)러.
-습니다/ㅂ니다, -고, -지만, -은/는.
ㅅ Deletion (for vowel-initial suffixes only): If the suffix starts with a vowel, the ㅅ from the verb stem is deleted.
낫- becomes 나-
짓- becomes 지-
젓- becomes 저-
붓- becomes 부-
-아/어요, -았/었어요): After ㅅ deletion, choose -아 or -어 based on the last remaining vowel in the stem.
나- (last vowel ㅏ) + -아요 = 나아요
지- (last vowel ㅣ) + -어요 = 지어요
저- (last vowel ㅓ) + -어요 = 저어요
부- (last vowel ㅜ) + -어요 = 부어요
-(으)면, -(으)러, -(으)세요): Even though the ㅅ is deleted, the verb retains its original "consonant-final stem" status. Therefore, use the forms with 으.
낫- (becomes 나-) + -(으)면 = 나으면 (NOT 나면)
짓- (becomes 지-) + -(으)러 = 지으러 (NOT 지러)
붓- (becomes 부-) + -(으)세요 = 부으세요 (NOT 부세요)
ㅅ is never deleted. Attach the suffix directly.
낫- + -습니다 = 낫습니다
짓- + -고 = 짓고
젓- + -지만 = 젓지만
붓다 (to pour/swell):
붓다 stem 붓-) | Result |
붓- | |
-어요) | |
ㅅ | 부- | |
ㅜ and "consonant stem" status) | 부- + -어요 = 부어요 | 부어요 |
-습니다) | |
ㅅ | 붓- | |
붓- + -습니다 = 붓습니다 | 붓습니다 |
-(으)면 type | Yes | |
ㅅ, retain "consonant status" | 부- + -(으)면 = 부으면 | 부으면 |
When To Use It
ㅅ irregular pattern applies to a finite yet frequently used set of verbs and adjectives in Korean, making their correct conjugation essential for daily communication. You will encounter these forms in a wide range of contexts, from describing physical conditions to common daily activities.- Describing Recovery or Improvement: The verb
낫다(natta) is commonly used to express recovery from illness or an improvement in a situation. 감기가 다 나았어요.(My cold has recovered completely.)경제가 점점 나아지고 있어요.(The economy is getting better little by little.)- Actions of Creation or Construction:
짓다(jitda) is versatile, meaning "to build," "to make," or "to compose." 새 집을 지었어요.(I built a new house.)이 노래는 제가 지었어요.(I composed this song.)- Actions of Mixing or Stirring:
젓다(jeotda) is used for stirring liquids or mixing ingredients. 커피를 잘 저으세요.(Please stir your coffee well.)수프를 계속 저어야 해요.(You have to keep stirring the soup.)- Actions of Pouring or Swelling:
붓다(butda) has two main meanings: "to pour" and "to swell." 컵에 물을 부어요.(I pour water into the cup.)아침에 얼굴이 자주 부어요.(My face often swells in the morning.)- Actions of Connecting or Continuing:
잇다(itta) means "to connect," "to link," or "to continue." 두 단어를 이어서 말해 보세요.(Try saying the two words connected together.)그는 가문의 명맥을 이었습니다.(He continued the family line.)- Other common uses: The verb
긋다(to draw a line) also follows this pattern. For example,선을 그으세요.(Please draw a line.) Theㅅirregular verbs are integral to daily Korean expressions and functional vocabulary at the A2 level.
When Not To Use It
ㅅ irregular rule to all verbs ending in ㅅ. However, a significant number of ㅅ-final verbs are regular, meaning their ㅅ is never dropped, regardless of the following suffix. Misapplying the irregular rule to these verbs will lead to incorrect and unnatural-sounding Korean.ㅅ verbs.ㅅ verbs include:웃다(utda): to laugh씻다(ssitda): to wash벗다(beotda): to take off (clothes, shoes)빼앗다(ppaeatda): to snatch, to take away솟다(sotda): to soar, to rise up빗다(bitda): to comb
ㅅ is always retained, and you conjugate them as you would any other regular verb. The choice between -아/어요 and -았/었어요 forms is still determined by the final vowel of the stem (which includes the ㅅ in this case).짓다 (to build) with the regular 씻다 (to wash):짓다 (to build) | Regular 씻다 (to wash) |지어요 | 씻어요 |지었어요 | 씻었어요 |지으면 | 씻으면 |지으러 | 씻으러 |씻다 maintains its ㅅ in all conjugations, and consequently, does not require the 으 in 씻으면 or 씻으러 because its stem already ends in a consonant. If you were to say 시어요 instead of 씻어요, it would sound incorrect and potentially confusing, perhaps resembling 쉬어요 (to rest).Common Mistakes
ㅅ irregular due to specific points of confusion. Awareness of these common pitfalls can significantly accelerate your mastery of the rule.- Over-generalizing the
ㅅdeletion: The most frequent error is droppingㅅfrom regularㅅverbs. Remember,웃다,씻다, and벗다are always regular. Saying우어요instead of웃어요is a direct consequence of this mistake. Always verify if the verb is irregular before deletingㅅ. For example,아이가 웃어요(The child laughs) is correct, not아이가 우어요. - Incorrect vowel choice for
-아/어요: After deletingㅅ, you might become unsure whether to attach-아요or-어요. The rule remains the same: look at the vowel immediately preceding the deletedㅅ. 낫다(낫-): The vowel isㅏ. After deletion,나-takes-아요->나아요.짓다(짓-): The vowel isㅣ. After deletion,지-takes-어요->지어요.젓다(젓-): The vowel isㅓ. After deletion,저-takes-어요->저어요.- Forgetting the "Ghost Consonant" for
-(으)면,-(으)러,-(으)세요: This is a critical nuance. While theㅅdisappears, the verb stem is still treated as consonant-final for suffixes that require으before them. Using나면instead of나으면is a classic mistake. This implies a lack of understanding of the underlying phonological structure. The presence of으is essential for the natural flow of these specific grammatical structures. For instance,감기가 나으면 좋겠어요(I hope my cold gets better) is correct;감기가 나면 좋겠어요is incorrect. - Confusing
ㅅirregular withㄷirregular: Both involve consonant deletion and a similar phonetic motivation. However,ㄷirregular verbs like듣다(to listen) changeㄷtoㄹbefore vowels, whileㅅirregular verbs simply deleteㅅ. 듣다(ㄷ irregular):듣+-어요->들어요젓다(ㅅ irregular):젓+-어요->저어요
나아요 as 날아요 (flies) or 지어요 as 질어요 (is damp).Memory Trick
Memorizing which ㅅ verbs are irregular and which are regular can be challenging. A simple memory trick can help you quickly recall the most common regular ㅅ verbs, allowing you to assume others are irregular unless proven otherwise. This strategy focuses on isolating the exceptions to the irregular rule.
Remember the "Three Commons" for regular ㅅ verbs:
- 웃다 (utda, to laugh): You laugh (웃) when you see something funny. The ㅅ stays.
- 씻다 (ssitda, to wash): You wash (씻) your hands. The ㅅ stays.
- 벗다 (beotda, to take off): You take off (벗) your clothes. The ㅅ stays.
These three verbs are highly frequent in daily conversation. If a ㅅ-final verb is not 웃다, 씻다, or 벗다 (and a few other less common regular ㅅ verbs like 빼앗다, 솟다, 빗다), it is generally safe to assume it is an irregular verb and apply the ㅅ deletion rule. This mental shortcut reduces the cognitive load of distinguishing between the two types. When in doubt, mentally check if the verb fits one of the "Three Commons" or consult a reliable dictionary that indicates irregularity.
Real Conversations
Understanding the grammatical rule is one aspect; observing its application in natural, everyday Korean conversations is another. The ㅅ irregular verbs appear frequently in both spoken and written exchanges, reflecting their common usage in describing states, actions, and desires. These examples illustrate their usage in various casual and semi-formal contexts.
Scenario 1
A
요즘 감기는 좀 어때? (How's your cold these days?)B
응, 많이 나았어! 걱정해줘서 고마워. (Yeah, it's much better! Thanks for worrying.)_Explanation_: 낫다 (to recover) is conjugated to 나았어 (past casual) after ㅅ deletion and -았어 attachment. This is a very common exchange among friends or family.
Scenario 2
이 수프는 계속 저어야 바닥에 안 눌어붙어요. (You have to keep stirring this soup so it doesn't stick to the bottom.)
_Explanation_: 젓다 (to stir) is conjugated to 저어야 (have to stir) from 젓- + -어야 after ㅅ deletion. This structure is common in recipes or when giving advice.
Scenario 3
새로운 아이디어를 함께 지어내는 것이 중요합니다. (It is important to create new ideas together.)
_Explanation_: 짓다 (to make/compose) is conjugated to 지어내는 (present progressive modifying noun) from 짓- + -어내다 + -는 것. ㅅ deleted before 어. This shows its use in more professional settings.
Scenario 4
어제 너무 많이 걸어서 다리가 부었어요. (I walked too much yesterday, so my legs swelled.)
_Explanation_: 붓다 (to swell) is conjugated to 부었어요 (past polite) from 붓- + -었어요 after ㅅ deletion. This is a natural way to describe an experience.
These examples demonstrate that ㅅ irregular forms are integral to expressing common concepts, and their correct usage is a marker of fluency. Paying attention to these forms in media and conversations will help solidify your understanding and naturalize your speech patterns.
Contrast With Similar Patterns
ㅅ irregular from other irregular patterns, particularly the ㄷ irregular, is crucial for accuracy and avoiding common errors.ㅅIrregular (ㅅ 불규칙):- The consonant
ㅅat the end of the verb or adjective stem is deleted when followed by a vowel-initial suffix. - The stem is still treated as consonant-final for suffixes like
-(으)면,-(으)러,-(으)세요, meaning the으is retained. - Example:
낫다(to recover) ->나아요(recovers),나으면(if recovers)
ㄷIrregular (ㄷ 불규칙):- The consonant
ㄷat the end of the verb stem changes toㄹwhen followed by a vowel-initial suffix. - The stem also behaves as consonant-final for
-(으)면type suffixes, but with the transformedㄹ(e.g.,들으면,걸으면). - Example:
듣다(to listen) ->들어요(listens),들으면(if listens)
ㅅ disappears entirely, whereas ㄷ changes its form to ㄹ.낫다 becoming 날아요 (flies) instead of 나아요 (recovers), or 듣다 becoming 드어요 instead of 들어요.ㅂIrregular (ㅂ 불규칙):- The consonant
ㅂat the end of the verb or adjective stem changes toㅜorㅗwhen followed by a vowel-initial suffix. Thisㅜorㅗthen combines with the following vowel. - Example:
덥다(to be hot) ->더워요(is hot),아름답다(to be beautiful) ->아름다워요(is beautiful).
ㅂ irregular results in a vowel change and combination, not a simple deletion. It's important to recognize that while all these rules serve a similar phonetic function, their specific mechanisms vary significantly.Progressive Practice
Mastering ㅅ irregular verbs requires systematic practice. Start with basic identification and conjugation, then move to sentence construction and finally to real-world application. This progressive approach solidifies your understanding and improves fluency.
- Level 1: Basic Conjugation & Identification
- Memorize the five most common irregulars: 낫다 (recover/better), 짓다 (build/make), 젓다 (stir), 붓다 (pour/swell), 잇다 (connect).
- Practice conjugating these five verbs with -아요/어요, -았어요/었어요, -(으)면, and -(으)세요. Focus on the ㅅ deletion and the
Conjugation of 짓다 (to build)
| Form | Suffix | Result |
|---|---|---|
|
Present
|
-어요
|
지어요
|
|
Past
|
-었어요
|
지었어요
|
|
Connective
|
-고
|
짓고
|
|
Negative
|
-지 않다
|
짓지 않다
|
|
Future
|
-을 거예요
|
지을 거예요
|
|
Formal
|
-습니다
|
짓습니다
|
Meanings
A specific class of Korean verbs where the final consonant 'ㅅ' is deleted when followed by a vowel-initial suffix.
Irregular Deletion
The phonological rule where ㅅ is elided.
“집을 짓다 -> 지어요”
“병이 낫다 -> 나아요”
Reference Table
| Form | Structure | Example |
|---|---|---|
|
Affirmative
|
Stem + -어요
|
지어요
|
|
Negative
|
Stem + -지 않다
|
짓지 않아요
|
|
Past
|
Stem + -었어요
|
지었어요
|
|
Question
|
Stem + -나요?
|
짓나요?
|
|
Connective
|
Stem + -고
|
짓고
|
|
Future
|
Stem + -을 거예요
|
지을 거예요
|
Formality Spectrum
상처가 나아지고 있습니다. (Medical/Personal)
상처가 나아지고 있어요. (Medical/Personal)
상처가 나아지고 있어. (Medical/Personal)
상처 나아짐. (Medical/Personal)
The 'ㅅ' Irregular Flow
Vowel Suffix
- 지어요 builds
Consonant Suffix
- 짓고 builds and
Examples by Level
밥을 지어요.
I am cooking rice.
감기가 나아요.
The cold is getting better.
길을 이어요.
I am connecting the road.
물을 부어요.
I am pouring water.
약을 먹고 나았어요.
I took medicine and got better.
집을 짓지 마세요.
Do not build the house.
선을 이어서 그리세요.
Connect the lines and draw.
물을 붓지 마세요.
Do not pour the water.
상처가 다 나아서 다행이에요.
It's a relief the wound has healed.
새로운 건물을 짓고 있습니다.
We are building a new building.
두 지점을 잇는 다리입니다.
It is a bridge connecting two points.
그릇에 물을 부었습니다.
I poured water into the bowl.
그는 집을 짓는 데 평생을 바쳤다.
He dedicated his life to building houses.
병이 나아가는 과정입니다.
It is the process of recovering from the illness.
두 선을 이으면 삼각형이 됩니다.
If you connect the two lines, it becomes a triangle.
물을 붓는 행위는 조심해야 합니다.
One must be careful when pouring water.
그는 운명을 짓는 자였다.
He was the one who shaped his destiny.
상처가 나아질 기미가 보이지 않는다.
There is no sign of the wound healing.
역사를 잇는 작업은 중요하다.
The work of connecting history is important.
그릇에 물을 부어 넘쳤다.
I poured water into the bowl and it overflowed.
그는 시를 짓고 있었다.
He was composing a poem.
병세가 나아지기를 간절히 바란다.
I earnestly hope the condition improves.
두 세계를 잇는 교량적 역할.
A bridging role connecting two worlds.
물을 부어 불을 껐다.
I poured water to extinguish the fire.
Easily Confused
Learners think all verbs ending in ㅅ are irregular.
Both involve consonant changes.
Both involve deletion.
Common Mistakes
벗어요
벗어요 (Wait, this is regular!)
짓어요
지어요
낫고
낫고 (Correct)
부어요
부어요 (Wait, this is irregular!)
짓어서
지어서
잇어요
이어요
낫지 않아요
낫지 않아요 (Correct)
짓은
지은
붓는
붓는 (Correct)
낫은
나은
짓어라
지어라
잇어라
이어라
붓어라
부어라
짓으니
지으니
Sentence Patterns
감기가 ___.
집을 ___.
물을 ___.
선을 ___.
Real World Usage
감기가 다 나았어요.
건물을 짓고 있습니다.
냄비에 물을 부으세요.
나았어?
두 점을 이으세요.
시를 짓다.
Check the list
Don't over-apply
Context is key
Politeness
Smart Tips
Check if it's on the irregular list before conjugating.
Always drop the ㅅ for irregular verbs.
Keep the ㅅ for irregular verbs.
Look up the verb in a dictionary; it will indicate if it's irregular.
Pronunciation
S-deletion
The 'ㅅ' is silent when dropped, so the vowel endings connect directly to the stem.
Statement
지어요 ↘
Neutral declarative tone.
Memorize It
Mnemonic
The 'S' is a shy ghost; it hides whenever a vowel comes near!
Visual Association
Imagine a letter 'S' wearing a cloak. When a vowel (like '아') walks by, the 'S' pulls its cloak over its head and disappears.
Rhyme
When the vowel starts to play, the 'S' will run away.
Story
Once there was a builder named 'S'. He loved to work, but he was very shy. Whenever he saw a vowel, he would hide behind a wall. But when he saw a consonant, he would stand tall and proud.
Word Web
Challenge
Write 5 sentences using '짓다' and '낫다' in both past and present tense.
Cultural Notes
Used in all formal and informal contexts.
Often keeps the 'ㅅ' longer or uses different endings.
Often shortens verbs to the stem.
The 'ㅅ' irregular rule is a remnant of Middle Korean phonology.
Conversation Starters
감기가 다 나았어요?
어떤 집을 짓고 싶어요?
이 선을 이으면 뭐가 돼요?
물을 부을까요?
Journal Prompts
Common Mistakes
Test Yourself
저는 밥을 ___.
Find and fix the mistake:
감기가 낫었어요.
물을 ___.
Arrange the words in the correct order:
All words placed
Click words above to build the sentence
I am building a house.
Answer starts with: b...
Match each item on the left with its pair on the right:
Use 잇다 + -어서
그는 시를 ___.
Score: /8
Practice Exercises
8 exercises저는 밥을 ___.
Find and fix the mistake:
감기가 낫었어요.
물을 ___.
나았어요 / 감기가 / 다
I am building a house.
짓다 -> ?
Use 잇다 + -어서
그는 시를 ___.
Score: /8
Practice Bank
10 exercises컵에 물을 _____. (Present Polite)
집을 ____ 싶어요. (Want to build)
나았어요 / 감기가 / 다
Match the pairs
If you stir it, it tastes better.
손을 씻어요.
선을 _____. (Polite Command)
Identify the irregular verb.
I made a name for my cat.
나으면 / 다시 / 몸이 / 만나요
Score: /10
FAQ (8)
No, only a few like 짓다, 낫다, 잇다, 붓다 are irregular.
It's a phonological rule to make pronunciation easier before vowels.
No, only to endings starting with a vowel.
No, '벗다' is a regular verb.
You have to memorize the small list of irregular verbs.
Yes, but remember the ㅅ stays before -습니다.
They are both irregular, but the mechanism is different.
Very common in daily life, especially with '낫다' and '짓다'.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Stem-changing verbs
Spanish changes vowels; Korean deletes consonants.
Liaison
French adds sounds; Korean removes them.
Strong verbs
German is vowel-based; Korean is consonant-based.
Godan verbs
Japanese is systematic; Korean is irregular.
Weak roots
Arabic is root-based; Korean is stem-based.
None
Chinese is isolating; Korean is agglutinative.
Learning Path
Prerequisites
Related Grammar Rules
Irregular ㅎ Verbs: Colors & 'Like that' (파랗다, 그렇다)
Overview The `ㅎ` irregular (히읗 불규칙 동사) rule governs a specific set of Korean descriptive verbs, primarily those...
The ㅂ Melting Rule: Hot & Cold Verbs (chupda/chuwoyo)
Overview The Korean `ㅂ` irregular rule, often dubbed the "Hot & Cold Verbs," is a crucial phonological phenomenon that...
Irregular Verbs (ㄷ → ㄹ): Walking, Hearing, Asking
Overview In Korean, verb conjugation often follows predictable patterns. However, certain verbs undergo systematic chang...
The 'Eu' Drop Pattern: Why 으 Disappears
Overview The Korean '으' (eu) drop pattern is a fundamental phonological rule governing the conjugation of many verbs an...
Korean Honorific Infix: Respecting the Subject (-(으)시)
Overview The Korean honorific infix `-(으)시` (\[-(eu)si]) serves a fundamental role in expressing **subject honorificat...
