ㅂ 불규칙
Quick answer: ㅂ 불규칙 means when the stem ends in ㅂ, it changes to 우 before -아/어요.
How to form it
춥다 → 추워요 · 덥다 → 더워요 · 맵다 → 매워요
In Korean: 춥다 → 추워요 덥다 → 더워요 맵다 → 매워요
What to know
You have been using 매워요 since unit 5 without knowing why. This is the rule behind it: the ㅂ becomes 우, and 우 plus 어 becomes 워. Not every ㅂ stem does this, but the common adjectives all do.
Examples
- 오늘 추워요.It's cold today.
- 여름에 더워요.It's hot in summer.
- 김치가 매워요.The kimchi is spicy.
Where it's taught
HanDa Level 1 (TOPIK I), Lesson 15: 오늘 날씨가 어때요? — How's the weather today?. Also in the Level 1 book.
Learned in the same lesson: -고.
Practise ㅂ 불규칙 out loud
In the HanDa app this is Level 1, Lesson 15 — drills, a speaking check and an AI teacher that corrects what you say. Free for 7 days.