Attach -아/어지다 to an adjective and you get the single most useful change-of-state pattern in Korean: 좋다 ("is good") → 좋아지다 ("get better"), 크다 ("is big") → 커지다 ("get bigger"), 따뜻하다 ("is warm") → 따뜻해지다 ("warm up"). You will use it constantly from your first weeks onward — every time the weather turns, your Korean improves, or a room grows quiet. And there is a real piece of grammar underneath it, not just a set of words to memorize: it exists because of how Korean adjectives fundamentally differ from English ones.
Why adjectives need 지다 to say "become"
In English, "warm" is an adjective and "become warm" borrows the verb become. Korean has no such split to borrow across, because Korean adjectives are already verbs — stative, or "descriptive," verbs. 따뜻하다 does not mean "warm"; it means "is warm," a complete predicate all by itself (따뜻해요 = "it's warm," a finished sentence). But a stative verb, by its nature, describes a state that holds — it has no built-in notion of change. To say the weather changed into being warm, you must convert that state into a change, and -아/어지다 is the converter. It takes a quality that simply is and puts it on a timeline: there was a before, and now there's an after.
날씨가 많이 따뜻해졌어요.
nalssiga mani ttatteutaejeosseoyo
The weather has gotten a lot warmer.
약을 먹으니까 몸이 많이 좋아졌어요.
yageul meogeunikka momi mani joajeosseoyo
After taking the medicine I felt much better.
밤이 되면 날씨가 추워져요.
bami doemyeon nalssiga chuwojeoyo
It gets cold once night falls.
This is why English collapses three ideas — "the soup is warm," "warm the soup," "the soup got warm" — into forms that all look related, while Korean keeps them cleanly apart: 따뜻하다 (is warm), 따뜻하게 하다 / 데우다 (make warm), 따뜻해지다 (become warm). The moment your English sentence means get / become / turn + adjective, the Korean is an adjective + 아/어지다.
The formation
The recipe is identical to the passive -아/어지다: take the adjective's -아/어 form — the same harmony form behind the present -아/어요 — and add 지다. Last vowel ㅏ/ㅗ → -아지다; everything else → -어지다; 하다 → 해지다. Irregular adjectives irregularize first, then 지다 rides along.
| Adjective | -아/어 form |
| Present | Meaning |
|---|---|---|---|---|
| 좋다 | 좋아 | 좋아지다 | 좋아져요 | get better |
| 많다 | 많아 | 많아지다 | 많아져요 | increase |
| 크다 (으-drop) | 커 | 커지다 | 커져요 | get bigger |
| 예쁘다 (으-drop) | 예뻐 | 예뻐지다 | 예뻐져요 | become prettier |
| 바쁘다 (으-drop) | 바빠 | 바빠지다 | 바빠져요 | get busy |
| 춥다 (ㅂ irregular) | 추워 | 추워지다 | 추워져요 | get cold |
| 따뜻하다 (하다) | 따뜻해 | 따뜻해지다 | 따뜻해져요 | warm up |
The present 져요 is simply 지 + 어요 contracting (ㅣ + ㅓ → ㅕ). And once an adjective takes 지다 it stops being an adjective and behaves like an action verb — it takes 진행형 (progressive) and verb-style modifiers, a shift explored in full on becoming with -아/어지다.
요즘 한국어가 점점 재미있어져요.
yojeum hangugeoga jeomjeom jaemiisseojeoyo
Korean is getting more and more fun for me these days.
우리 강아지가 그새 많이 커졌어요.
uri gang-ajiga geusae mani keojeosseoyo
Our puppy has grown so much in no time.
이사하고 나서 회사 일이 바빠졌어요.
isahago naseo hoesa iri bappajeosseoyo
Ever since I moved, work has gotten busy.
Gradual change, and how it reads in each tense
-아/어지다 tends to picture change as gradual — sliding along a scale rather than flipping a switch — which is why it loves the adverbs 점점 and 점차 ("gradually," "little by little"). In the past (-아/어졌어요), it reports a change that has already happened and now holds: 좋아졌어요 = "has gotten better (and is better now)." In the present (-아/어져요), it describes change as a general or ongoing tendency: 추워져요 = "it gets cold / it's getting cold."
봄이 되면서 낮이 점점 길어져요.
bomi doemyeonseo naji jeomjeom gireojeoyo
As spring comes on, the days are gradually getting longer.
요즘 물가가 너무 비싸졌어요.
yojeum mulgaga neomu bissajeosseoyo
Prices have gotten really expensive lately.
The trap: 좋아지다 ("get better") vs 좋아하다 ("like")
These two look nearly identical and mean entirely different things — mixing them up is one of the most common intermediate slips. Both start from 좋다 ("is good") and both begin 좋아…, but the endings send them to opposite meanings:
- 좋아지다 = 좋아 + 지다 → "get better / improve" (a change of state — this page).
- 좋아하다 = 좋아 + 하다 → "to like" (an emotion-verb formed with 하다).
처음엔 별로였는데 이제 한국 음식이 좋아졌어요.
cheoeumen byeollyeonneunde ije hanguk eumsigi joajeosseoyo
At first I wasn't into it, but now I've come to like Korean food (it's grown on me).
저는 매운 음식을 정말 좋아해요.
jeoneun maeun eumsigeul jeongmal joahaeyo
I really like spicy food.
The first says a state changed — food that wasn't appealing now is. The second states a standing preference. Keep the endings straight: 지다 = becomes, 하다 = likes. (For the broader 좋다 vs 좋아하다 tangle, see 좋아하다 vs 좋다.)
Common Mistakes
1. Using the plain adjective for a change of state. The bare adjective states what was, not what became.
❌ 봄이 오니까 날씨가 따뜻했어요.
Means only 'the weather was warm' — for 'got warm' you need 따뜻해졌어요.
✅ 봄이 오니까 날씨가 따뜻해졌어요.
bomi onikka nalssiga ttatteutaejeosseoyo
Now that spring's here, the weather has warmed up.
2. Confusing 좋아지다 with 좋아하다. 지다 = become better; 하다 = like.
❌ 운동을 시작하고 건강이 좋아했어요.
Wrong verb — 'my health improved' is 좋아졌어요, not the 'like' verb 좋아하다.
✅ 운동을 시작하고 건강이 좋아졌어요.
undong-eul sijakago geongang-i joajeosseoyo
After I started exercising, my health improved.
3. Attaching 지다 to the dictionary stem instead of the -아/어 form. Build on 좋아, 커 — not ×좋지다, ×크지다.
❌ 소리가 점점 크지고 있어요.
Wrong — build on the -아/어 form of 크다, which is 커: 커지고 있어요.
✅ 소리가 점점 커지고 있어요.
soriga jeomjeom keojigo isseoyo
The sound is getting louder and louder.
4. Ignoring the irregular before 지다. 춥다 is a ㅂ-irregular: 추워, not ×춥어.
❌ 밤에는 날씨가 춥어져요.
Wrong — 춥다 → 추워: 추워져요.
✅ 밤에는 날씨가 추워져요.
bameneun nalssiga chuwojeoyo
It gets cold at night.
Key Takeaways
- -아/어지다 on a descriptive verb (adjective) means "become / get [more] ADJ": 좋아지다, 커지다, 많아지다, 예뻐지다, 따뜻해지다.
- It exists because Korean adjectives are stative verbs and cannot express "becoming" on their own — 좋다 is only "is good," and 좋아지다 supplies the change English packs into "get / become."
- Build it on the adjective's -아/어 form, respecting each irregular first (춥다 → 추워 → 추워지다).
- It pictures change as gradual (loves 점점); past = change now complete, present = an ongoing tendency.
- Don't confuse 좋아지다 ("get better," -지다) with 좋아하다 ("like," -하다) — the ending is the whole difference.
Now practice Korean
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Start learning Korean→Related Topics
- Adjective + 지다: The Grammar of BecomingTOPIK 2 — A decision guide to Korean's three ways of saying 'become': adjective + -아/어지다 for a change in QUALITY (길어지다), noun + 이/가 되다 for becoming a CATEGORY (의사가 되다), and verb + 게 되다 for coming to be in a SITUATION (알게 되다). English uses one word for all three; Korean sorts by what follows 'become'.
- Becoming with -아/어지다: 예뻐지다, 좋아지다TOPIK 2 — How an adjective (a STATE) turns into an inchoative VERB (a CHANGE of state) with -아/어지다 — 예쁘다 → 예뻐지다 ('become pretty'), 좋다 → 좋아지다 ('get better'). Once an adjective takes -지다 it crosses the divide and starts taking verb endings (예뻐지는, 예뻐지고 있어요).
- -아/어지다 as PassiveTOPIK 3 — -아/어지다 on an action-verb stem builds an agentless passive/resultative (만들어지다 'be made', 지어지다 'be built') — the productive fallback for the many verbs that have no fused suffix passive — and why stacking both (보여지다) is the classic double-passive error.
- -게 되다: Coming to / Ending UpTOPIK 3 — V-게 되다 says a situation came about through circumstances rather than your own initiative — 알게 됐어요 'I found out', 살게 됐어요 'I ended up living [there]' — a high-frequency 'change of situation' pattern that also softens announcements.
- Spontaneous, Agentless -아/어지다TOPIK 5 — The spontaneous/potential use of -아/어지다 on certain verbs of perception, cognition, and volition — 느껴지다 'come to be felt', 믿어지다 'can bring oneself to believe', 써지다 'the pen writes' — expressing that something happens by itself or beyond one's control, mapping to English 'won't', 'can't bring myself to', and 'seems/feels'.