🇰🇷 Lesson 21: Irregular Verbs

By now you've probably met a few words that refused to behave. You'd expect 덥다 ("to be hot") to become 덥어요, but everyone says 더워요. 듣다 ("to listen") should be 듣어요, but it's 들어요. In Lesson 20 you said 아파요 ("it hurts") from 아프다, and in Lesson 19 you asked for help with 도와주세요 from 돕다. Today we explain every one of them.

First, the reassuring news: Korean "irregular" verbs are not random. English irregulars are a list you just memorise (go/went, eat/ate, buy/bought). Korean irregulars fall into seven small families, and every member of a family changes in exactly the same way. Learn the rule once, and it works for dozens of words.

🔥 1. The ㅂ family: ㅂ → 우

When a stem ending in ㅂ meets a vowel, the ㅂ turns into 우. Then 우 + 어 contracts to 워, just as 배우 + 어요 became 배워요 in Lesson 7.

Other everyday members: 귀엽다 → 귀여워요 (cute), 무겁다 → 무거워요 (heavy), 가볍다 → 가벼워요 (light), 반갑다 → 반가워요 (glad — yes, the 반갑습니다 you learned in Lesson 4!), 고맙다 → 고마워요 (thankful). A handy rule of thumb: almost every adjective ending in ㅂ is irregular, while most verbs ending in ㅂ are regular (see "look-alikes" below). "—" in the table means the honorific form isn't something you'd naturally say about a person.

Notice 반갑습니다 and 고맙습니다: before the consonant ending -습니다, the ㅂ stays. That's the "what does the ending start with?" rule in action.

👂 2. The ㄷ family: ㄷ → ㄹ

A handful of common verbs ending in ㄷ change the ㄷ to ㄹ before a vowel.

Before consonants, the ㄷ is back: 음악을 듣고 싶어요 (I want to listen to music), 걷지 마세요 (don't walk). Also note that the new ㄹ is a real consonant, so the 으 in -(으)세요 and -(으)면 stays: 들으세요, 걸으면.

😷 3. The ㅡ family: ㅡ disappears

When a stem ending in the vowel ㅡ meets -아/어, the ㅡ simply drops out. Then you choose 아 or 어 by looking at the vowel one syllable further back:

🎵 4. The 르 family: 르 → ㄹㄹ

Stems ending in 르 lose their ㅡ and grow an extra ㄹ: the ㄹ jumps onto the previous syllable as a final consonant. Then 라 or 러 follows the usual harmony.

Also: 자르다 → 잘라요 (cut), 누르다 → 눌러요 (press), 배부르다 → 배불러요 (full). A few 르 stems, such as 따르다 → 따라요 (follow, pour) and 들르다 → 들러요 (drop by), don't double the ㄹ — they just follow the ㅡ rule. They're rare at this level; if you meet one, a dictionary will show it.

🏠 5. The ㄹ family: ㄹ drops before ㄴ, ㅂ, ㅅ

This family is the mirror image of the others: with -아/어 endings it's perfectly regular (살다 → 살아요). It changes before consonants. Two rules:

So that's why Lesson 19 had 창문을 여세요 from 열다. And here's a fun trap: 사세요 can come from 살다 ("Where do you live?" 어디에 사세요?) or from 사다 ("Please buy it!"). Context always settles it. As mentioned above, many grammars count this ㄹ-dropping as a regular, automatic rule — but it's still something you must actively apply.

🩹 6. The ㅅ family: ㅅ disappears (and nothing contracts)

A small group of verbs lose their final ㅅ before a vowel. The unusual part: after the ㅅ disappears, the vowels do not contract. 나 + 아요 stays 나아요 (not 나요), and 지 + 어요 stays 지어요 (not 져요). The 으 of -(으)세요 also stays.

낫다 is the star of this family after Lesson 20: 감기가 다 나았어요. ("My cold is completely better.") 짓다 appears in 집을 짓다 (build a house) and 이름을 짓다 (choose a name). 붓다 describes swelling: 얼굴이 부었어요 (my face is puffy).

🎨 7. The ㅎ family: colour & "how/so" adjectives

Adjectives ending in ㅎ — mostly colours and the 이렇다/그렇다/저렇다/어떻다 set — lose the ㅎ before a vowel, and the vowel + 아/어 fuses into ㅐ (ㅑ fuses into ㅒ). Before 으, the ㅎ and the 으 both vanish.

You've been using this family since your first week: 어때요? ("How is it?") and 그래요? ("Really? / Is that so?") are ㅎ-irregulars! And 어떻게 ("how") keeps its ㅎ because -게 starts with a consonant. (Modifier forms like 빨간 are previewed here; you'll learn modifiers properly in Lesson 25.)

🚫 Regular Look-alikes — the ones that don't change

This is where learners slip: not every word ending in ㅂ, ㄷ, ㅅ or ㅎ is irregular. These common words are completely regular:

🇰🇷 Cultural note — weather talk and 고와요. Korean small talk runs on ㅂ-irregulars: 오늘 정말 더워요! in the humid August heat, 많이 추워요? in January, and 안 매워요? as a caring question to a foreign guest at dinner. And 곱다 — one of only two words with the 와 form — has a gentle, slightly old-fashioned warmth. Koreans use 고와요 to praise a grandmother's hanbok, soft skin, or a kind heart (마음이 고와요): a beautiful word to know.

💬 Dialogue — Catching Up

Jisu and Minho meet on a cold winter day. Spot the irregulars!

Did you catch them? ㅅ: 나았어요 · ㅡ: 바빠요 · ㅂ: 추워요, 쉬워요, 고마워요, 가까워요, 도와줄게요 · ㄷ: 들을, 걸을, 걸어요 · ㄹ: 만들 · 르: 몰라요. And two look-alikes: 맵지 (consonant ending, so ㅂ stays) and 입으세요 (입다 is regular).

Irregular verbs are one of the places where every learner — and plenty of Korean children — makes mistakes for a while. That's fine. Each time you catch yourself saying 덥어요 and correct it to 더워요, the right form gets a little more automatic. You're not bad at irregulars; you just haven't said them enough times yet.

✍️ Practice

🧠 Check Your Understanding

❓ Common Questions

🔮 Looking Ahead

In Lesson 22: Weather & Seasons, your new ㅂ-irregulars take centre stage: 덥다, 춥다 and friends are how Koreans talk about every season — 여름은 더워요, 겨울은 추워요 — so you'll get plenty of natural practice straight away.