ㅎ-Irregular Adjectives: 어떻다, 그렇다, 빨갛다

A small family of adjectives ends in the consonant ㅎ, and almost all of them are irregular. Two clusters make up the ㅎ-irregular (ㅎ 불규칙): nearly every color word — 빨갛다 (red), 파랗다 (blue), 노랗다 (yellow), 까맣다 (black), 하얗다 (white) — and the manner-demonstrative set 이렇다 / 그렇다 / 저렇다 / 어떻다 ("be like this / like that / like how"). These look obscure in the dictionary, but they generate some of the highest-frequency words in the language: 그래요 ("that's right / okay"), 어때요? ("how is it?"), 어떤 ("what kind of"), 그런 ("such"), even the connector 그런데 ("by the way"). Learn the two irregular branches once, and a whole web of everyday Korean falls open.

The two branches

Everything hinges on what the ending starts with. There are exactly two behaviors:

Hold onto the second branch — the vowel fusion to ㅐ — because it is the part that has no parallel anywhere else in the language, and it is where every English speaker's guess goes wrong.

Branch 1: before -(으)ㄴ and friends, the ㅎ just drops

When the ending would normally begin with 으 — the attributive -(으)ㄴ, the conditional -(으)면, the future -(으)ㄹ, the causal -(으)니까 — the ㅎ disappears and the ending clips straight onto the remaining vowel. No 으 is inserted. So 그렇다 gives 그런 (not ×그렇은), and 빨갛다 gives 빨간 (not ×빨갛은).

The attributive column (그런, 빨간, 하얀, 어떤) is treated alongside the other stem-changing attributives on the irregular attributives page. But the same drop feeds a cluster of connectors you use constantly — because 그렇다 + a 으-ending is where they come from:

• 그렇다 + -(으)면 → 그러면 ("then / in that case"), contracted to 그럼
• 그렇다 + -(으)ㄴ데 → 그런데 ("by the way / but")
• 그렇다 + -(으)니까 → 그러니까 ("so / that's why")

Every one of those everyday words is a ㅎ-irregular adjective wearing a 으-ending. Recognizing the pattern turns a memorized list back into a single rule.

Branch 2: before -아/어, the vowel fuses to ㅐ (the part that matters)

Here is the branch with no analogue elsewhere. When a ㅎ-irregular stem meets the vowel ending -아/어 (which drives the present -아/어요, the past -았/었-, and connectives like -아/어서), the ㅎ drops and the stem vowel fuses with the ending into ㅐ. So you never get ×그렇어요 or ×빨갛아요 — you get 그래요 and 빨개요.

Walk 그렇다 through it: drop the ㅎ from 렇 → 러, then the vowel ㅓ merges with the ending's 어 into ㅐ, so 러 becomes 래 → 그래요. The same fusion, mechanically:

Notice the one twist in the bottom row: 하얗다 has the stem vowel ㅑ (하 + 얗), and ㅑ + ㅐ fuses one step further into ㅒ, giving 하얘요, not ×하얘요's plainer cousin ×하애요. The rule is still "fuse to ㅐ," just iotized to ㅒ because the vowel underneath was already iotized. Everything else lands on a clean ㅐ.

The past tense stacks predictably on the same fused vowel — 그렇다 → 그랬어요 (geuraesseoyo), 어떻다 → 어땠어요 (eottaesseoyo), 빨갛다 → 빨갰어요 (ppalgaesseoyo):

The high-frequency payoff

This is a rare corner of Korean grammar where the irregular forms are more common than the dictionary forms. You will meet these far more often than you'll meet 그렇다 or 어떻다 sitting in a dictionary:

• 그래요 / 그래 — "that's right," "okay," "sure," "I see" — the all-purpose agreement token
• 어때요? / 어때? — "how is it?", "what do you think?", "how about it?"
• 어떤 — "what kind of / which" (어떻다 → attributive): 어떤 색을 좋아해요?
• 그런 / 이런 / 저런 — "such a / this kind of / that kind of"
• 그런데 · 그러니까 · 그러면(그럼) — the workhorse connectors above

Master the ㅎ-irregular and you are not learning a fringe rule — you are unlocking the connective tissue of casual conversation.

The crucial exception: 좋다 is REGULAR

Here is the trap that runs the other direction. Not every adjective ending in ㅎ is irregular. The single most common one — 좋다 ("be good / nice / likeable") — is completely regular. It keeps its ㅎ in spelling and takes the plain endings: 좋다 → 좋아요 (never ×좨요), attributive 좋은 (never ×존). The ㅎ simply falls silent in pronunciation ([조아요]), but the word behaves like any consonant-stem adjective.

The same goes for a set of verbs ending in ㅎ, which are all regular too: 넣다 → 넣어요 (put in), 놓다 → 놓아요 (put down), 낳다 → 낳아요 (give birth). Only the color / manner adjectives drop the ㅎ. If you catch yourself producing ×좨요 or ×넣애요, you've over-applied the irregular.

One more guard: plain consonant endings keep the ㅎ

The drop only happens before 으-endings and -아/어. Before other consonant endings — -고, -지, -게, -습니다 — the ㅎ stays in the spelling (it just aspirates or tenses the next consonant in speech). So 어떻다 gives 어떻게 [어떠케] ("how"), 그렇다 gives 그렇지 [그러치] ("right?") and 그렇고 [그러코] ("and it's so"). Don't try to fuse those.

Common Mistakes

1. Regularizing the vowel ending — ×그렇어요, ×빨갛아요. The ㅎ must drop and the vowel must fuse to ㅐ.

2. Leaving the ㅎ in the color word — ×빨갛아요, ×하얗아요.

3. Over-applying the drop to 좋다 — ×좨요, ×존 사람. 좋다 is regular.

4. Inserting 으 before the attributive — ×그렇은, ×빨갛은. The ㅎ drops and -ㄴ attaches directly.

5. Fusing before a consonant ending — ×어때게, ×그러지. Before -게/-지/-고 the ㅎ stays written.

Key Takeaways

• The ㅎ-irregular set = color adjectives (빨갛다, 파랗다, 노랗다, 까맣다, 하얗다) + manner demonstratives (이렇다, 그렇다, 저렇다, 어떻다).
• Before 으-endings the ㅎ drops, no 으 inserted: 그렇다 → 그런 / 그러면 / 그러니까.
• Before -아/어 the ㅎ drops and the vowel fuses to ㅐ (ㅒ after ㅑ): 그렇다 → 그래요, 빨갛다 → 빨개요, 하얗다 → 하얘요.
• The payoff forms — 그래요, 어때요, 어떤, 그런, 그런데 — are among the most common words in Korean.
• 좋다 is REGULAR (좋아요, 좋은), as are the verbs 넣다·놓다·낳다. Only colors and manner-demonstratives drop the ㅎ.
• Plain consonant endings keep the ㅎ in spelling: 어떻게, 그렇지, 그렇고.