1 · Particles
The subject particle 이/가
the subject marker
이/가 marks the subject — who or what does something, or is somewhere — and puts the weight on it.
The subject particle is 이 after a consonant and 가 after a vowel: 책이, 사람이, 친구가, 비가. Like every particle it is written onto the noun.
It marks the grammatical subject, and above all a subject that is new or that the sentence is describing. 비가 와요, "it is raining", is literally "rain comes". Something you notice, something that exists or is missing, the part of a thing that is being described — all take 이/가: 여기 고양이가 있어요, 시간이 없어요, 머리가 아파요. The last one is "I have a headache": English says "I have", Korean names the aching head as the subject.
Three common words change their shape before 가. 저 (I, polite) becomes 제가, 나 (I, casual) becomes 내가, and 누구 (who) becomes 누가. The plain combinations are not standard, so "who came?" is 누가 왔어요?, and the answer starts with 제가 if it was you.
Two verbs put 이/가 on a noun that English treats as a complement: 아니에요, "is not" (학생이 아니에요), and 되다, "become" (의사가 되다). And a sentence can hold a topic and a subject at once: 저는 배가 아파요, "as for me, the stomach hurts" — I have a stomach ache.
The form
| after a consonant | 책이, 사람이, 물이 |
| after a vowel | 친구가, 비가, 커피가 |
| I (polite) as the subject | 제가 |
| I (casual) as the subject | 내가 |
| who as the subject | 누가 |
| with there is | 시간이 있어요. |
The rules one by one
The form this topic is aboutThe word that calls for it
이 follows a consonant and 가 a vowel.
가방이 무거워요.The bag is heavy.
저, 나 and 누구 change their shape before 가: 제가, 내가, 누가.
누가 왔어요?Who came?
What you suddenly notice, and what exists or is missing, takes 이/가.
눈이 와요!It is snowing!
A body part or a feature that is being described is the subject, even where English says "I have".
저는 배가 아파요.I have a stomach ache.
With 아니에요 the noun in front of it takes 이/가 too.
저는 학생이 아니에요.I am not a student.
A closer look
A topic and a subject in one sentence
Korean is comfortable with two nouns at the front of a sentence, one with 은/는 and one with 이/가. 서울은 사람이 많아요 is "as for Seoul, people are many": Seoul has a lot of people. 저는 눈이 나빠요 is "as for me, the eyes are bad": I have poor eyesight.
English rebuilds such sentences with "have" or a possessive, and English speakers tend to do the same in Korean — 제 눈이 나빠요 is correct, but it sounds as if you were talking about your eyes rather than about yourself. The pattern with a topic and a subject is the everyday one.
Exceptions and special cases (1)
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the subject is 저, 나, 너 or 누구
they become 제가, 내가, 네가 and 누가.
누가 이 케이크를 만들었어요?Who made this cake?
These are old contractions that became the only forms. Because 네가 (you) and 내가 (I) sound almost the same in Seoul speech, many people say 니가 for "you" when talking to friends; in writing it stays 네가.
How to spot it
- 이
- 가
- 제가
- 내가
- 누가
- 있어요
- 없어요
- 아니에요
Example sentences
비가 많이 와요.It is raining a lot.
누가 김 선생님이세요?Which of you is Mr Kim?
제 방에 창문이 없어요.My room has no window.
제가 민수예요.I'm Minsu (the one you are looking for).
오늘은 날씨가 좋아요.The weather is good today.
동생이 지금 자요.My younger sibling is asleep right now.
8 more example sentences
버스가 와요.The bus is coming.
냉장고에 우유가 있어요.There is milk in the fridge.
오늘은 시간이 없어요.I don't have time today.
누가 전화했어요?Who phoned?
이 가방이 제 거예요.This bag is mine.
저는 다리가 아파요.My legs hurt.
저 사람이 제 동생이에요.That person is my younger sibling.
창밖에 새가 있어요.There is a bird outside the window.
Worth knowing (1)
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The honorific subject 께서
When the subject is someone you owe great respect — a grandparent, a teacher in a formal setting — 께서 can replace 이/가, and the verb takes the honorific -시-. In everyday speech 이/가 with an honorific verb is enough.
할머니께서 주무세요.Grandmother is sleeping.
The trap English speakers fall into
Watch out
Before the subject particle, 저 becomes 제, and 나 becomes 내. The plain combination of word and particle is simply not used, so "I" as the subject is 제가 in polite speech and 내가 among friends.
The particle is i after a consonant and ga after a vowel, and "I" and "who" change shape before it: jega, naega, nuga.
Your turn
10 exercises on this topic. Your answers are checked in the browser; none of them leaves your device.