1 · Irregular verbs
The vowel 으 drops: 쓰다 → 써요
the disappearing eu
A stem ending in the vowel 으 loses it before -아요/어요: 쓰다 becomes 써요, 바쁘다 becomes 바빠요.
Many common verbs and adjectives have a stem that ends in the vowel 으: 쓰다 (to write), 크다 (to be big), 바쁘다 (to be busy), 아프다 (to hurt, to be ill), 예쁘다 (to be pretty). When an ending that begins with 아 or 어 follows — the polite present -아요/어요 or the past -았/었- — the 으 simply disappears, and the consonant in front of it takes the new vowel: 쓰 and 어요 give 써요, never 쓰어요.
Which vowel comes in is decided by the syllable before the 으, not by the 으 itself. If the stem has only one syllable, as in 쓰다, 크다 and 끄다 (to switch off), there is nothing before it, and the ending is always 어: 써요, 커요, 꺼요. If there is a syllable before it, look at its vowel: a or o there calls for 아 (바쁘다 → 바빠요, 아프다 → 아파요), and any other vowel for 어 (예쁘다 → 예뻐요, 슬프다 → 슬퍼요).
Endings that begin with a consonant leave the stem alone: 바쁘고, 아프지만, 쓰세요, 큽니다. Korean grammars do not even count this as irregular, because every stem of this shape behaves the same way and there is no regular verb in 으 to learn beside it. For a learner it is still a change to know, and the first one met: 배고파요 (I am hungry) and 아파요 (it hurts) are among the first things anybody says.
English speakers slip in two ways. The first is keeping the 으 and writing 바쁘어요, which looks logical and does not exist. The second is choosing the vowel by the 으 and writing 바뻐요; the vowel belongs to the syllable before. Saying the right form aloud a few times fixes both, and 바빠요, with the same vowel twice, is easy to remember.
The form
| one syllable: always 어 | 쓰다 → 써요, 크다 → 커요 |
| a or o before 으: 아 | 바쁘다 → 바빠요, 아프다 → 아파요 |
| another vowel before 으: 어 | 예쁘다 → 예뻐요, 슬프다 → 슬퍼요 |
| past | 썼어요, 바빴어요, 예뻤어요 |
| before a consonant: no change | 쓰고, 바쁘지만, 아프세요 |
The rules one by one
The form this topic is about
Before an ending that starts with 아 or 어, the 으 of the stem drops.
친구한테 편지를 써요.I am writing a letter to a friend.
A stem of one syllable always takes 어.
이 바지는 저한테 좀 커요.These trousers are a bit big for me.
In a longer stem, the vowel of the syllable before 으 decides: a or o gives 아, anything else 어.
저는 요즘 정말 바빠요.I am really busy these days.
The past is built on the same changed form.
어제는 하루 종일 머리가 아팠어요.Yesterday I had a headache all day.
An ending that starts with a consonant leaves the stem unchanged.
일이 바쁘지만 재미있어요.Work is busy, but it is fun.
A closer look
Why the 으 gives way
으 is the weakest vowel in Korean. It is the vowel the language adds when it needs to break up consonants, as in 버스 for “bus” or 커피숍 for “coffee shop”, and it carries almost no colour of its own. When it meets the full vowel 아 or 어 of an ending, it is the one that disappears.
The same changed stem appears in every ending that begins with 아 or 어, not only in the polite present: 바빠서(because I am busy)아파도(even if it hurts)써야 해요(I have to write) Once you know 바빠요, all of them follow from it.
How to spot it
- 써요
- 커요
- 바빠요
- 아파요
- 예뻐요
- -아요/어요
Example sentences
배고파요. 같이 밥 먹어요.I am hungry. Let's eat together.
이 꽃이 정말 예뻐요.These flowers are really pretty.
불 좀 꺼 주세요.Could you switch off the light, please?
동생 방이 아주 커요.My younger sibling's room is very big.
어제 친구한테 이메일을 썼어요.Yesterday I wrote an email to a friend.
고양이가 많이 아파요?Is your cat very ill?
8 more example sentences
영화가 너무 슬퍼요.The film is so sad.
오늘은 기분이 좀 나빠요.I am in a bit of a bad mood today.
저는 돈을 조금씩 모아요.I save up a little money at a time.
비가 와요. 우산을 써요.It is raining. I am putting up my umbrella.
아이가 어제 배가 아팠어요.The child had a stomach ache yesterday.
그 가방 정말 예뻤어요.That bag was really pretty.
약이 너무 써요.The medicine is very bitter.
지난주에는 정말 바빴어요.Last week I was really busy.
Worth knowing (2)
-
One 쓰다, several meanings
쓰다 means to write, to use, to wear on the head or face (a hat, glasses, an umbrella) and, as an adjective, to taste bitter. These are different words that happen to share a spelling, and all of them give 써요.
저는 컴퓨터를 쓸 때 안경을 써요.I wear glasses when I use the computer.
-
Hungry and full
배고프다 (to be hungry) belongs here and gives 배고파요. Its opposite, 배부르다 (to be full), ends in 르 and gives 배불러요, with a second l — a different group with its own topic.
배고파요? 저는 배불러요.Are you hungry? I am full.
The trap English speakers fall into
Watch out
The new vowel is chosen by the syllable before 으. In 바쁘다 that syllable is 바, with a, so the ending is 아: 바빠요. 바뻐요 is a common slip, even among native speakers typing quickly, but it is wrong.
Drop the eu, then let the syllable before it choose a or eo.
Your turn
9 exercises on this topic. Your answers are checked in the browser; none of them leaves your device.