Korean 은/는 vs 이/가 Explained: Topic Marker vs Subject Marker

Day 9 Recap

What you learned in Day 9:

Particles attach after nouns and mark their role in the sentence
Form changes by 받침: 은/는, 이/가, 을/를, 으로/로
이다: a copular particle — attaches to a noun to form the predicate (학생이에요 / 의사예요)
아니다: an adjective — complement (noun + 이/가) + adjective predicate (학생이 아니에요)

Today, we look at the difference between 은/는 and 이/가. Day 9 grouped them together as particles with the same 받침 pattern — but in practice, they do completely different things.

First: What They Have in Common

은/는 and 이/가 are both particles that attach at the subject position.

나는 학생이에요.    ← 나 (I) = subject position
내가 학생이에요.    ← 나 (I) = subject position

Both mark "this word is the subject." That's the common ground.

Wait — 나 + 가 = 내가?

In Korean, a few pronouns change form when 이/가 attaches to them.
나  + 가  →  내가   (나가 ✗)
저  + 가  →  제가   (저가 ✗)
너  + 가  →  네가   (in speech, often 니가)
This is why you hear "내가 했잖아!" and "제가 할게요" in dramas — not 나가 or 저가. These contractions, along with 이것/그것/저것 → 이게/그게/저게 and more, are covered fully in Day 12.

So if they both mark the subject, why are there two?

은/는 and 이/가 are not about grammatical role — they differ in the nature of the information they signal. Even in the same subject slot, the choice of particle tells the listener something different.

English doesn't make this distinction:

The cat is cute.

Just "the cat" — one form for every situation. Whether the cat is a topic, new information, or being emphasized, English handles it through word order and intonation. Korean uses particles.

은/는 — The Topic Marker

은/는 signals: "I'm about to say something about this word."

The closest English equivalent: "As for ___"

나는 학생이에요.
→ As for me — I'm a student.

서울은 커요.
→ As for Seoul — it's big.

What is a "topic"?

Something already in the conversation, or something you're introducing as: "Let me say something about this." Once a topic has been established, you keep using 은/는 to refer back to it.

A: 민준이 알아요?   Do you know Minjun?
B: 네, 민준이는 알아요.   Yes, Minjun — I know him.
   (민준이 already entered the conversation → 은/는 picks it up)

은/는 carries a contrast undertone

은/는 often implies "this one yes, but something else maybe not" — a silent comparison hovering in the background.

커피는 마셔요.
→ Coffee, I drink.  (implied: but not tea)

날씨는 좋아요.
→ The weather, at least, is nice.  (implied: other things aren't)

나는 괜찮아.
→ As for me — I'm fine.  (implied: but what about you?)

This is why Korean sounds layered even in simple sentences. The particle does a lot of work.

은/는 can appear outside the subject slot

Here's an important point: 은/는 isn't locked to the subject. It can attach to objects, complements — anywhere — and it brings the same "as for this" + contrast meaning.

밥을 먹었어요.     I ate rice.          (neutral — object particle 을)
밥은 먹었어요.     Rice, I ate.         (contrast — at least I ate)

커피를 마셔요.     I drink coffee.      (neutral)
커피는 마셔요.     Coffee, I drink.     (contrast — not other things)

When 을/를 becomes 은/는, the grammatical role (object) stays the same, but contrast is layered on top. 은/는 has no fixed slot. Wherever it attaches, it signals "as for this" + contrast.

✏️ Activity 1: Reading 은/는

Read each sentence and write what role 은/는 is playing in the parentheses. (topic introduction / contrast / picking up a mentioned topic)

1. A: 영화 봤어요?   Did you watch the movie?
   B: 영화는 봤어요. 근데 숙제는 못 했어요.
      The movie, I watched. But homework, I couldn't do.
   → 영화는: (              )
   → 숙제는: (              )

2. A: 언니 알아요?   Do you know 언니?
   B: 네, 언니는 알아요.   Yes, 언니 — I know her.
   → 언니는: (              )

3. 한국어는 알아요. 근데 일본어는 몰라요.
   Korean, I know. But Japanese, I don't.
   → 한국어는: (              )

이/가 — The Subject Marker

이/가 marks: "This word is the subject of this sentence." Unlike 은/는, 이/가 is subject-position only.

Three situations where 이/가 is used:

1. New information — something entering the conversation for the first time

어, 비가 와요!
→ Oh, it's raining!  (noticing rain for the first time — "rain" = new information)

고양이가 들어왔어요.
→ A cat came in.  (first appearance — cat = new information)

New participants get introduced with 이/가. Once they're established in the conversation, 은/는 takes over.

고양이가 들어왔어요.  고양이는 귀여워요.
     ↑ new info (이/가)          ↑ already mentioned (은/는)

2. Exclusive emphasis — "this one specifically"

이/가 singles out a specific target: "Not something else — this one."

내가 할게.
→ I'll do it.  (not someone else — me specifically)

민준이가 했어.
→ It was Minjun.  (not someone else — Minjun specifically)

이게 맛있어요.
→ This is the one that's delicious.  (not something else — this one)
   *(이게 = 이것 + 이 contracted — covered fully in Day 12)*

A pair worth memorizing from K-dramas:

"내가 할게."   →  I'll do it.       (strong intent, emphasis on I)
"나는 괜찮아."  →  As for me, I'm fine.  (contrast, implication)

Same word 나, one particle change, completely different feel.

3. Answering "who / what" questions

누가 전화했어요?   Who called?
→ 민준이가 전화했어요.   Minjun called.  (specifically Minjun — new information)

뭐가 맛있어요?   What's delicious?
→ 이게 맛있어요.   This is.  (specifically this — new information)

Answers to 누가 and 뭐가 always take 이/가 — you're identifying someone or something for the first time.

✏️ Activity 2: Reading 이/가

Write what role 이/가 is playing in each sentence. (new information / exclusive emphasis / answering a question)

1. A: 누가 샀어요?   Who bought it?
   B: 지수가 샀어요.   Jisu bought it.
   → 지수가: (              )

2. 어, 강아지가 있어요!   Oh, there's a dog!
   → 강아지가: (              )

3. A: 누가 할 거예요?   Who's going to do it?
   B: 제가 할게요.   I will.
   → 제가: (              )

4. A: 뭐가 더 좋아요?   What do you like more?
   B: 사과가 더 좋아요.   Apples — I like them more.
   → 사과가: (              )

Side by Side

	은/는	이/가
Name	Topic marker	Subject marker
Core function	"As for ___", contrast	New information, exclusive emphasis
Other positions	Yes — carries contrast anywhere	No — subject slot only
English equivalent	None ("As for ___")	None (handled by word order / intonation)
Form (with 받침)	은	이
Form (no 받침)	는	가

Same sentence, different particle — nuance comparison

날씨가 좋아요.
→ The weather is nice.  (neutral — new observation)

날씨는 좋아요.
→ The weather is nice...  (contrast — "at least the weather is")

오빠가 먹었어요.
→ Older brother ate it.  (he specifically — new information)

오빠는 먹었어요.
→ Older brother ate it...  (but what about the others?)

내가 할게.
→ I'll do it.  (emphasis — me, not anyone else)

나는 할게.
→ As for me, I'll do it.  (topic — and you?)

은/는 and 이/가 are one of the hardest parts of Korean for English speakers. If it doesn't click 100% right now, that's completely normal. The sense builds with exposure — the more sentences you meet, the more natural it feels.

✏️ Activity 3: 은/는 or 이/가?

Read the context hint and fill in the blank with 은, 는, 이, or 가.

1. (looking out the window)
   어, 눈___ 와요!
   Hint: first time noticing — new information
   (눈 = snow)

2. A: 누가 만들었어요?   Who made it?
   B: 제 오빠___ 만들었어요.   My older brother did.
   Hint: answering "who" — specific identification

3. 피자___ 좋아요. 근데 파스타___ 별로예요.
   Pizza is good. But pasta — not so much.
   Hint: talking about pizza, comparing with pasta

4. A: 수업 어때요?   How's class?
   B: 수업___ 재미있어요. 근데 숙제___ 너무 많아요.
      Class is interesting. But homework — way too much.
   Hint: class already in the conversation + contrast

5. A: 오늘 뭐 해요?   What are you doing today?
   B: 공부___ 해요. 운동___ 안 해요.
      Studying, I'm doing. Exercise, I'm not.
   Hint: studying yes, exercise no — contrast

Mini Quiz: Day 10

Q1. What do 은/는 and 이/가 have in common?

A) Both can attach to the object position
B) Both are particles that attach at the subject position
C) Both introduce new information
D) Both only attach to nouns without 받침
Answer: ____

Q2. Someone asks "누가 했어요?" — which answer is correct?

A) 민준이는 했어요.
B) 민준이가 했어요.
Answer: ____

Q3. In "밥은 먹었어요," what is 은/는 doing?

A) Marking 밥 as the subject
B) Marking 밥 as new information
C) Elevating 밥 to a topic while adding contrast
D) Using 은 instead of 을 because of the 받침
Answer: ____

Q4. Explain the difference between these two sentences in one sentence.

내가 할게.
나는 할게.

→ ___________________________________________

(Answers: Q1-B, Q2-B, Q3-C, Q4: example — "내가 할게" emphasizes that I specifically will do it (not anyone else); "나는 할게" sets "me" as the topic — as for me, I'll do it — with a softer, more comparative feel)

Answer Key

Activity 1

1. 영화는: topic introduction + contrast simultaneously
          (picks up "movie" from the question, then contrasts with homework)
   숙제는: contrast (watched the movie but couldn't do homework)

2. 언니는: picking up a mentioned topic
          (언니 was already introduced in the question)

3. 한국어는: contrast (Korean yes, Japanese no)

Activity 2

1. 지수가: answering a question (누가 → specifically Jisu)
2. 강아지가: new information (first time noticing the dog)
3. 제가: exclusive emphasis (I specifically will — not someone else)
4. 사과가: exclusive emphasis / answering a question (뭐가 → specifically apples)

Activity 3

1. 눈이   (이/가 — new information)
   눈 [nun]: 받침 ㄴ → 이
   → 눈이 와요!

2. 오빠가  (이/가 — answering a question, 오빠 has no 받침 → 가)

3. 피자는 ... 파스타는  (은/는 — contrast)
   피자: no 받침 → 는 / 파스타: no 받침 → 는

4. 수업은 ... 숙제는  (은/는 — topic + contrast)
   수업: 받침 ㅂ → 은 / 숙제: no 받침 → 는

5. 공부는 ... 운동은  (은/는 — contrast)
   공부: no 받침 → 는 / 운동: 받침 ㅇ → 은

Day 10 Checklist

은/는 and 이/가 are both particles that attach at the subject position — that's the shared ground
The difference is not grammatical role — it's the nature of the information being signaled
은/는 = topic marker — "as for ___", picking up a mentioned topic, contrast
이/가 = subject marker — new information, exclusive emphasis ("this one specifically"), answering who/what
은/는 can attach outside the subject slot — it brings contrast wherever it goes
이/가 is subject-position only
Answering "누가/뭐가?" → 이/가
Referring back to an established topic → 은/는
First mention → 이/가 / second mention onward → 은/는

"Next up: Day 11 — 에 vs 에서, (으)로, 하고/와·과, 도, 만, 한테"

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Topic vs. Subject — 은/는 and 이/가