Core Grammar Rule: ~아/어지다
This pattern attaches to adjectives to express a change of state, meaning "to become" or "to get" something. It describes a gradual transformation from one condition to another.
Meaning & Usage
Meaning: It signifies that the quality or state described by an adjective has changed over time. For example, 따뜻하다 (to be warm) becomes 따뜻해지다 (to get warm).
When to use: Use it to talk about changes in weather (getting colder), health (getting better), appearance (becoming prettier), difficulty (getting harder), or feelings (becoming happier). It implies a process of change, not an instant switch.
Conjugation Rules
Rule: The form depends on the last vowel of the adjective stem.
Vowel ㅏ or ㅗ: Add ~아지다.
좋다 (good) → 좋 + 아지다 → 좋아지다 (to get better)
밝다 (bright) → 밝 + 아지다 → 밝아지다 (to get brighter)
Other Vowels: Add ~어지다.
춥다 (cold) → 추우 + 어지다 → 추워지다 (to get colder) (ㅂ irregular)
예쁘다 (pretty) → 예쁘 + 어지다 → 예뻐지다 (to become prettier) (ㅡ irregular)
하다 Adjectives: 하다 changes to 해지다.
깨끗하다 (clean) → 깨끗해지다 (to get clean)
복잡하다 (complicated) → 복잡해지다 (to get complicated)
Vowel ㅏ/ㅗ: ~아지다 / Other Vowels: ~어지다 / 하다: ~해지다
Native Nuance & Mistakes
Understanding when and when not to use ~아/어지다 will make your Korean sound much more natural.
Use with Adjectives, Not Action Verbs
Context: ~아/어지다 is almost exclusively used to show a change in the state described by an adjective. Attaching it to an action verb like 가다 (to go) or 먹다 (to eat) is incorrect. For changes related to actions, other grammar patterns are used.
Example: 예뻐지다 (to become pretty) is correct because 예쁘다 is an adjective. However, 가아지다 is incorrect.
Natural vs. Unnatural Combinations
Context: While grammatically possible, some combinations sound awkward. For instance, 맛있어지다 (to become delicious) is used, but often Koreans would prefer to say 맛있게 되다 (to turn out delicious) or simply 맛있어졌어요 (it has become delicious) to describe food that improved during cooking. The key is that ~아/어지다 implies a natural, gradual change.