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Korean grammar

Korean irregular verbs: the ㅡ drop, ㅂ → 우 and vowel merging

Most Korean verbs that look irregular follow one of a few sound rules. Stems ending in ㅡ drop it before the ending (크다 → 커요, 아프다 → 아파요). In the ㅂ irregular, a final ㅂ turns into 우 before a vowel (덥다 → 더워요). And vowel merging squeezes the 아요/어요 ending into the stem's last vowel (오 + 아요 → 와요). Learn the rule once and the same change carries into the past tense and every other 아/어 form.

Examples are written in Hangul. New to it? Start with the hangul chart.

In short

  • ㅡ drop: a stem ending in ㅡ loses it, and the vowel before decides 아 or 어: 크다 → 커요, 예쁘다 → 예뻐요, 바쁘다 → 바빠요, 아프다 → 아파요.
  • ㅂ irregular: a final ㅂ becomes 우 before a vowel: 덥다 → 더워요, 춥다 → 추워요, 어렵다 → 어려워요. Some ㅂ verbs are regular and keep it: 입다 → 입어요.
  • Vowel merging is regular Korean, not an exception: 가 + 아요 → 가요, 오 + 아요 → 와요, 주 + 어요 → 줘요, 되 + 어요 → 돼요, 마시 + 어요 → 마셔요, and 하다 → 해요.
  • The same changes carry into the past: 커요 → 컸어요, 아파요 → 아팠어요, 더워요 → 더웠어요.
  • Other families you will meet: ㄹ drops before ㄴ, ㅂ and ㅅ (살다 → 사니까, 삽시다), 르 doubles the ㄹ (모르다 → 몰라요), and ㅅ drops before a vowel (짓다 → 지어요).

ㅡ disappears before 아/어

When a stem's last vowel is ㅡ, the ㅡ drops out and the previous vowel decides 아 or 어. 크다 → 커요 (big). 예쁘다 → 예뻐요 (pretty). Don't say 크어요 or 예쁘어요 — the ㅡ is gone. Learn these as whole forms.

  • 커요

    keoyo

    is big

  • 예뻐요

    yeppeoyo

    is pretty

  • 가방이 커요

    The bag is big. (polite)

아프다 → 아파요 (the ㅡ-irregular)

아프다 means 'to hurt / be sick / be in pain'. It's ㅡ-IRREGULAR: the stem-final ㅡ drops before the ending, giving 아파요 (NOT 아프어요). The frame is [body part] + 가/이 아파요: 머리가 아파요 = 'My head hurts', 배가 아파요 = 'My stomach hurts.' For 'I'm sick' generally, 아파요 stands alone.

  • 아파요

    apayo

    hurts / is sick

  • 배가 아파요

    My stomach hurts.

  • 머리가 아파요

    My head hurts

The ㅂ → 우 irregular

덥다 ('to be hot') and 춥다 ('to be cold') are ㅂ-IRREGULAR: the final ㅂ becomes 우 before the ending, so 덥다 → 더워요 and 춥다 → 추워요 (NOT 덥어요 / 춥어요). Use them for weather: 오늘 더워요 = 'It's hot today.'

  • 더워요

    deowoyo

    is hot (weather)

  • 추워요

    chuwoyo

    is cold (weather)

  • 추워서 집에 있어요

    It's cold, so I stay home.

  • 오늘 더워요

    It's hot today

  • 오늘 추워요

    It's cold today

Vowel merge — why it's 와요, not 오아요

The 아요/어요 ending blends into the stem's last vowel. 가 + 아요 → 가요 (ㅏ + ㅏ: one drops). 오 + 아요 → 와요 (ㅗ + ㅏ = ㅘ). 주 + 어요 → 줘요 (ㅜ + ㅓ = ㅝ). 되 + 어요 → 돼요 (ㅚ + ㅓ = ㅙ). 하다 is special: 하 + 여요 → 해요. This is the rule behind 가요, 와요, 봐요 and 해요.

  • 뭘 마셔요?

    What do you drink?

  • 뭘 먹어요?

    What are you eating?

  • 작은 게 예뻐요

    The small one is pretty.

  • 친구가 와요

    My friend is coming.

  • 여기서 뭘 먹어요?

    What do you eat here?

  • 전 빵을 먹어요

    I eat bread

Check yourself

Questions from the course. Pick an answer to check it; nothing is saved.

  1. 1.Make 크다 polite ('it's big'):

  2. 2.Make 예쁘다 polite ('it's pretty'):

  3. 3.'My head hurts.' Pick the Korean.

  4. 4.'My throat hurts.' Pick the Korean.

  5. 5.'It's hot today.' Pick the Korean.

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