Lesson 16 · -아/어요: 하다, ㅡ & Irregular Forms
Hyeju’s Beginner Korean Grammar Class · Lesson 16
-아/어요: 하다, ㅡ & Irregular Forms
Build accurate polite forms with 하다, ㅡ, 르, ㅂ, ㄷ, ㅅ, and ㅎ patterns, regular contrasts, examples, and six practice sets.
Introduction & Review
Lesson 05 introduced -아/어요, and Lesson 15 practiced negatives. Now make the everyday positive forms accurate. V means an action verb; A means a descriptive verb. Start from the dictionary form and remove 다. What remains is the stem. The changes below apply to -아/어요; do not apply them automatically to every ending.
Today’s Grammar
For an ordinary stem, use 아요 after the last stem vowel ㅏ or ㅗ and 어요 after other vowels. Familiar contractions include 가다 → 가요 and 보다 → 봐요. Today’s seven groups show forms that need extra attention. ㅡ dropping is a predictable vowel change, generally classified as regular; 하다 → 하여요 → 해요 is the special 하다 pattern. The 르, ㅂ, ㄷ, ㅅ, and ㅎ groups below include lexical irregulars. Learn the word and its form together.
1 · 하다 and ㅡ
| Group | How to form it | Learn the pair |
|---|---|---|
| 하다 | 하다 uses 하여요, usually contracted to 해요. | 공부하다 → 공부해요 |
| ㅡ | Drop the final ㅡ before 아/어. Look at the vowel in the preceding syllable: ㅏ/ㅗ → 아요; other vowels → 어요. A one-syllable ㅡ stem uses 어요. | 바쁘다 → 바빠요; 아프다 → 아파요; 쓰다 → 써요; 크다 → 커요 |
For 바쁘다, the preceding syllable 바 contains ㅏ, so 바빠요. For 쓰다 there is no preceding syllable, so 써요. Keep these as word pairs before trying unfamiliar words.
2 · 르 and ㅂ
| Group | Today’s pattern | Useful limits |
|---|---|---|
| 르 | For these 르-irregular words, add ㄹ to the previous syllable and change 르 to 라/러 before 아/어: 모르다 → 몰라요; 빠르다 → 빨라요. | This is not every 르 word: 따르다 → 따라요 (follow); 푸르다 → 푸르러요 (be blue/green). These are recognition examples, not today’s quiz. |
| ㅂ | For these ㅂ-irregular words, ㅂ changes to 우 before a vowel ending, giving 워요: 춥다 → 추워요; 덥다 → 더워요. | 돕다 → 도와요 and 곱다 → 고와요 are the important 와요 pairs. Some ㅂ words are regular: 입다 → 입어요 (wear); 잡다 → 잡아요 (hold). |
3 · ㄷ, ㅅ, and ㅎ
| Group | Learn the form | Compare a regular word |
|---|---|---|
| ㄷ | These irregulars change ㄷ to ㄹ before a vowel ending: 듣다 → 들어요; 걷다 (walk) → 걸어요. | 닫다 → 닫아요 (close). A final ㄷ alone does not tell you the pattern. |
| ㅅ | These irregulars drop ㅅ before a vowel ending: 낫다 → 나아요; 짓다 → 지어요. Keep the vowels visible in the spelling. | 씻다 → 씻어요 (wash); 웃다 → 웃어요 (smile/laugh). |
| ㅎ | For today’s color adjective, ㅎ drops and the vowel changes: 하얗다 → 하얘요. Another common pair: 빨갛다 → 빨개요 (be red). | 좋다 → 좋아요 (be good). Do not remove ㅎ from every word. |
Hyeju’s Note · The Ending Matters
Before consonant-initial -고, the stems in today’s irregular examples stay as 듣고, 춥고, 짓고, 하얗고, 모르고. 들어요 does not make the dictionary stem 들어-. Lesson 17 uses this contrast. This is a focused map of the curriculum’s seven groups, not a complete inventory of every Korean irregular.
Examples
Compare with similar grammar
LESSON 5
-아/어요 (basic rule)
친구를 만나요. 밥을 먹어요.Lesson 5’s basic rule: ㅏ/ㅗ → 아요, any other vowel → 어요. Today’s stems are the exceptions.
Review Lesson 5 →LESSON 21
-았/었어요
어제는 정말 바빴어요.Irregular stems change the same way in the past: 바쁘다 → 바빠요 → 바빴어요.
Look ahead: Lesson 21 →| Pattern | Rule | Example |
|---|---|---|
| 하다 | 하 → 해 | 공부하다 → 공부해요 |
| ㅡ | ㅡ drops; the vowel before it picks 아/어 | 바쁘다 → 바빠요, 쓰다 → 써요 |
| ㅂ | ㅂ → 우 + 어요 = 워요 | 덥다 → 더워요 |
| 르 | 르 → ㄹ라/ㄹ러 | 모르다 → 몰라요 |
Mini Dialogue
A: 오늘 바빠요?
oneul bappayo · Are you busy today?
B: 네, 한국어를 공부해요.
ne, hangugeoreul gongbuhaeyo · Yes, I am studying Korean.
A: 이 단어를 알아요?
i daneoreul arayo · Do you know this word?
B: 아니요, 몰라요.
aniyo, mollayo · No, I do not.
알아요 = know, from 알다. It is recognition vocabulary in this dialogue; the main practice uses 모르다.
Common mistakes
쓰어요 → 써요; 모르아요 → 몰라요; 듣어요 → 들어요; 돕어요 → 도와요; 낫아요 → 나아요; 하얗아요 → 하얘요.
Do not memorize a blanket rule from the final letter. 듣다 is irregular, while 닫다 is regular. Use a dictionary to check an unfamiliar word.
ㅡ drops, and the vowel before it (ㅏ) picks 아요: 바빠요.
In ㅂ-irregular adjectives, ㅂ becomes 우: 더워요.
르 stems double the ㄹ: 모르다 → 몰라요.
하다 always becomes 해요.
Mini practice · six questions
All sentences below are new. Try each one before opening the answer.
- Fill in the blank이 가방은 저한테 너무 ______. (크다)
Check answer
이 가방은 저한테 너무 커요.
ㅡ drops. With a one-syllable stem, add 어요: 커요.
- Fill in the blank · ㅂ이 떡볶이는 조금 ______. (맵다)
Check answer
이 떡볶이는 조금 매워요.
ㅂ → 워요: 매워요. “This tteokbokki is a bit spicy.”
- Choose the correct form점심을 안 먹었어요. 배가 (고프아요 / 고파요).
Check answer
고파요
ㅡ drops; the vowel before it is ㅗ, so 아요: 고파요.
- Choose the correct form한국어 발음이 (어렵어요 / 어려워요).
Check answer
어려워요
어렵다 is ㅂ-irregular: 어려워요.
- Find and fix the mistake제 친구는 노래를 잘 부르어요.
Check answer
제 친구는 노래를 잘 불러요.
부르다 is a 르 verb: 불러요.
- Say it in KoreanI write in my diary every day.
Check answer
저는 매일 일기를 써요.
쓰다 → 써요 (ㅡ drops).
Today’s Key Point
Remove 다 to find the stem; check the ending before changing it.
Word pairs beat letter-only guesses: 듣다 → 들어요, 닫다 → 닫아요.
Before -고: 듣고, 춥고, 모르고.
M.A. in Korean Language Education · Certified Korean language teacher
About the educator →