Topic and Subject Particles: 은/는 and 이/가
Learn the two most famous Korean particles: the topic marker 은/는 and the subject marker 이/가, how to attach them, and when to choose each one.
Mr. Gaon · Grammar, vocabulary & TOPIKWhat you will learn in this lesson
- Attach 은/는 and 이/가 correctly after consonants and vowels
- Use 은/는 to introduce a topic or show contrast
- Use 이/가 for new information and to answer “who” or “what”
- Know the special forms 제가, 내가 and 누가
Today’s topic is famous among Korean learners. Many people say 은/는 and 이/가 are the hardest part of beginner Korean. Don’t worry. We will start with clear rules, and you will get a feeling for them with practice.
What is a particle?
A particle is a small tag that comes right after a noun. It tells you the job of that noun in the sentence. English uses word order for this, but Korean uses particles. Because of this, Korean word order can be a little flexible, but the verb always stays at the end.
Today we learn two particles:
은/는 — the topic particle. It means “as for …” or “talking about …”.
이/가 — the subject particle. It points to the one who does the action or has the quality.
topic: as for N
- After a consonant (batchim): 은 — 선생님은, 책은.
- After a vowel (no batchim): 는 — 저는, 친구는.
- Use it to say what the sentence is about, especially at the start of a conversation.
- Use it to compare or contrast two things.
- 저는 학생이에요. jeoneun haksaengieyo.I am a student. (As for me, I’m a student.)
- 제 동생은 고등학생이에요. [제 동생은 고등학쌩이에요] je dongsaengeun godeunghaksaengieyo.My younger sibling is a high school student.
- 오늘은 월요일이에요. [오느른 워료이리에요] oneureun woryoirieyo.Today is Monday.
- 커피는 좋아요. 녹차는 싫어요. [커피는 조아요. 녹차는 시러요] keopineun joayo. nokchaneun sireoyo.Coffee, I like. Green tea, I don’t like.
subject: N (does / is …)
- After a consonant (batchim): 이 — 동생이, 책이.
- After a vowel (no batchim): 가 — 친구가, 날씨가.
- Use it for new information, for example when something appears or happens.
- Use it to answer questions with 누가 (who) or 뭐가 (what).
- 비가 와요. biga wayo.It’s raining. (Rain comes.)
- 날씨가 좋아요. [날씨가 조아요] nalssiga joayo.The weather is nice.
- 동생이 아파요. dongsaengi apayo.My younger sibling is sick.
- 저기 버스가 와요! jeogi beoseuga wayo!Look, the bus is coming over there!
Attaching the particles
| Noun | Ends in | Topic 은/는 | Subject 이/가 |
|---|---|---|---|
| 선생님 | consonant | 선생님은 | 선생님이 |
| 책 | consonant | 책은 | 책이 |
| 물 | consonant | 물은 | 물이 |
| 친구 | vowel | 친구는 | 친구가 |
| 커피 | vowel | 커피는 | 커피가 |
| 저 (I) | vowel | 저는 | 제가 |
| 누구 (who) | vowel | 누구는 | 누가 |
Special forms: 저 + 가 → 제가, 나 + 가 → 내가, 누구 + 가 → 누가.
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Notice the special forms in the last rows. We never say 저가 or 누구가. It is always 제가 and 누가. Memorize these three as single words.
Rule 1: Old information vs. new information
A helpful way to think about it: 은/는 marks something already in the conversation, and 이/가 brings in something new.
Imagine a story: “Once upon a time, there was a king. The king had three daughters.” In Korean, the first “king” (new) takes 이/가, and the second “king” (already known) takes 은/는.
옛날에 왕이 있었어요. 그 왕은 딸이 셋 있었어요.
You don’t need to understand every word in that sentence yet. Just look at 왕이 (new) and 왕은 (known).
Rule 2: Question words take 이/가
When the question word is the subject, like 누가 (who) or 뭐가 (what), the answer also uses 이/가. This is because the answer is the new, important information.
누가 와요? — 민지가 와요. “Who is coming? — Minji is coming.”
뭐가 맛있어요? — 비빔밥이 맛있어요. “What is tasty? — Bibimbap is tasty.”
If you answered 민지는 와요, it would sound like “Minji (at least) is coming, but maybe not others.” That brings us to the third rule.
Rule 3: 은/는 shows contrast
When you compare two things, use 은/는 on both. It adds a feeling of “as for this one… but as for that one…”.
저는 고기를 먹어요. 동생은 고기를 안 먹어요. “I eat meat. My sibling doesn’t eat meat.”
Even with one item, 은/는 can hint at a contrast. For example, 오늘은 바빠요 can suggest “Today I’m busy (but maybe not on other days).”
Same words, different focus
- 제가 민수예요. jega minsuyeyo. I am Minsu. (It’s me — I’m the Minsu you are looking for.) 이/가 puts the focus on the subject: “me, not someone else”.
- 저는 민수예요. jeoneun minsuyeyo. I am Minsu. (Introducing myself.) 은/는 introduces the topic. This is the normal self-introduction.
- 날씨가 좋아요. [날씨가 조아요] nalssiga joayo. The weather is nice. A simple report of what you see now.
- 날씨는 좋아요. [날씨는 조아요] nalssineun joayo. The weather is nice (but something else is not). Contrast: maybe the trip was too long.
Words for this lesson
- 친구 chingu friend
- 동생 dongsaeng younger sibling
- 날씨 nalssi weather
- 비 bi rain
- 오늘 oneul today
- 좋아요 [조아요] joayo is good / I like it
- 싫어요 [시러요] sireoyo I don’t like it
- 맛있어요 [마시써요] masisseoyo is delicious
- 바빠요 bappayo is busy
- 아파요 apayo is sick / hurts
- 누가 nuga who (as subject)
Who is that?
A handy trick: N은요/는요?
In the dialogue, Jisu asks 톰 씨는요? This is a short way to say “And you?” or “What about …?” Just add 은요 or 는요 to a name or noun. 저는요? means “What about me?” and 내일은요? means “What about tomorrow?”
Check quiz
Q1. Choose the correct topic form of 선생님.
Q2. How do you say “I” as a subject with 가?
Q3. 누가 커피를 마셔요? — Which answer is natural?
Q4. “I like apples, but my sister doesn’t.” Which particle shows the contrast on “my sister”?
Q5. “Look! The bus is coming!” Fill in: 버스__ 와요!
Q6. How do you say “What about tomorrow?”
You did a great job with a difficult topic. Even advanced learners still think about 은/는 and 이/가 sometimes. Listen for them in dramas and songs, and the feeling will grow naturally.
Key points
- 은 after a consonant, 는 after a vowel: topic, “as for”.
- 이 after a consonant, 가 after a vowel: subject.
- 은/는 for known topics and contrast; 이/가 for new information.
- Answers to 누가 and 뭐가 use 이/가.
- Special forms: 제가, 내가, 누가.
- N은요/는요? means “What about N?”
Recommended official free resources
- Korean Language Teaching & Learning Center — National Institute of Korean Language
- Nuri-Sejong Hakdang (free e-textbooks) — King Sejong Institute Foundation
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