Topic and Subject

Korean Grammar 1

Course 1 · Chapter 3 · Topic and Subject Particles

🏷️ Topic and Subject Particles — 은/는 과 이/가

Korean Grammar 1, chapter 1 showed that Korean marks the job of each noun with a small particle. The two most common particles mark the noun that the sentence is about. There are two pairs: 은/는 marks the topic and 이/가 marks the subject. Each pair is two forms of the same particle: you pick one by looking at the last sound of the noun. The choice between the two pairs is the hard part of Korean for English speakers, so this chapter takes it step by step.

The rule in one box Step 1 (the form): if the noun ends in a consonant (a block with a final), use 은 or 이. If it ends in a vowel, use 는 or 가.
Step 2 (the job): use 은/는 for what the sentence is about (known, or contrasted); use 이/가 for the new thing, or the one that answers "who?" or "what?".

Step 1: Choosing the form by the final sound

Look only at the last block of the noun. If it has a final consonant (batchim, Korean Alphabet 1, chapter 9), the noun ends in a consonant. If it does not, the noun ends in a vowel. Remember that ㅇ at the start of a block is silent, but a ㅇ at the bottom of a block is a real final (the "ng" sound).

Noun ends in	Topic	Subject
a vowel	는 neun	가 ga
a consonant	은 eun	이 i

Noun	Ends in	+ Topic	+ Subject
친구 chingu friend	vowel	친구는 chingu-neun	친구가 chingu-ga
사과 sagwa apple	vowel	사과는 sagwa-neun	사과가 sagwa-ga
고양이 goyang-i cat	vowel	고양이는 goyang-i-neun	고양이가 goyang-i-ga
책 chaek book	consonant (ㄱ)	책은 chaeg-eun [채근]	책이 chaeg-i [채기]
물 mul water	consonant (ㄹ)	물은 mul-eun [무른]	물이 mul-i [무리]
학생 haksaeng student	consonant (ㅇ)	학생은 haksaeng-eun	학생이 haksaeng-i

When the particle starts with ㅇ (은 and 이), the final of the noun moves across to it (Korean Grammar 1, chapter 2, rule A): 물은 is said "mu-reun", not "mul eun".

Watch out: a final ㅇ counts as a consonant 학생 ends in ㅇ at the bottom of its last block, so it takes 은/이. A noun like 고양이 ends in the silent ㅇ at the top of its last block (the vowel 이), so it takes 는/가. Look at where the ㅇ sits.

Watch out: the subject particle 이 looks like other words 이 is also the word for "this" (이 책, this book) and for "tooth". Only the position tells you which: the particle is joined to the end of a noun and has no space before it.

Step 2: Choosing the job

The topic: 은/는 means "as for…"

The topic is what you are talking about. It is usually something already known to both speakers, or something you are setting up to say a comment about. It can also set one thing in contrast with another. The English "as for" is the nearest, though Korean uses it far more often than English does.

Sentence	Meaning	Note
저는 학생이에요. jeo-neun haksaeng-ieyo.	I am a student. (As for me, a student.)	introducing yourself; sets the topic (this sentence is built in Korean Grammar 1, chapter 5)
물은 차요. mul-eun chayo.	The water is cold. (As for the water…)	the water is already in view
저는 커피를 마셔요. 친구는 물을 마셔요. jeo-neun keopi-reul masyeoyo. chingu-neun mul-eul masyeoyo.	I drink coffee; my friend drinks water.	contrast: I do this, my friend does that

The subject: 이/가 means "it is X that…"

The subject marker points at the thing that does or is something, and is used when this is new information, or when the noun answers a question word like "who?". Question words are marked with 이/가: 누가 nu-ga (who is the one that…?) and 뭐가 mwo-ga (what is it that…?).

Sentence	Meaning	Note
고양이가 있어요. goyang-i-ga isseoyo.	There is a cat.	introduces something new into the conversation
누가 와요? nu-ga wayo?	Who is coming?	a question word as the subject takes 가
친구가 와요. chingu-ga wayo.	My friend is coming. (It is my friend who comes.)	the answer fills the "who?"
책이 많아요. chaeg-i manayo.	There are many books.	describing what is there

The same noun, both ways

With 이/가: stating a fact, or answering	With 은/는: talking about it, or contrasting
물이 차요. mul-i chayo. The water is cold. (I notice and report it.)	물은 차요. mul-eun chayo. The water, now, is cold. (Perhaps the coffee is not.)
제가 마셔요. je-ga masyeoyo. I'm the one who drinks it.	저는 마셔요. jeo-neun masyeoyo. As for me, I drink it.

Watch out: the pronouns change before 가 저 (I, polite), 나 (I, casual) and 너 (you, casual) change their vowel before the subject particle: 저 + 가 → 제가 jega, 나 + 가 → 내가 naega, 너 + 가 → 네가 nega. Before the topic particle there is no change: 저는, 나는, 너는.

Habits that help

New thing → 이/가; known thing or contrast → 은/는. A story often starts with 이/가 ("There was a cat") and carries on with 은/는 ("The cat slept").
Introductions and general facts use 은/는 (저는 학생이에요).
Both marks never sit on the same noun. A noun is topic or subject, not both.
In casual speech either can be dropped when the meaning is clear: 친구 와요. This course writes them in full.
Not sure? A question word (누가, 뭐가) always takes 이/가. Otherwise try 은/는; a native speaker will usually understand you either way.

🗣️ In Use — 실제 예문

The rule in short exchanges. Spot the 이/가 on the new information and the 은/는 on the known one.

① Who is coming?

A: 누가 와요? nu-ga wayo? Who is coming?

B: 친구가 와요. chingu-ga wayo. My friend is coming.

A: 친구는 학생이에요? chingu-neun haksaeng-ieyo? Is your friend a student?

② Coffee or water?

A: 커피 마셔요? keopi masyeoyo? Do you drink coffee?

B: 저는 커피를 마셔요. 친구는 물을 마셔요. jeo-neun keopi-reul masyeoyo. chingu-neun mul-eul masyeoyo. I drink coffee. My friend drinks water.

📋 Quick Reference — 요약표

Particle	After	Use	Example
는	vowel	topic, contrast	친구는
은	consonant	topic, contrast	책은
가	vowel	subject, new information, "who/what?"	고양이가, 누가
이	consonant	subject, new information	물이
Pronouns before 가		저 → 제, 나 → 내, 너 → 네	제가

✏️ Try It Yourself — 연습

Work out the answer first, then click to check.

1. Add the topic particle: 친구, 책, 학교.

Show answer

친구는, 책은, 학교는. (학교 ends in a vowel, so 는.)

2. Add the subject particle: 물, 사과, 학생.

Show answer

물이, 사과가, 학생이.

3. Why does 고양이 take 는/가 and not 은/이?

Show answer

Its last block 이 has no final consonant: the ㅇ is the silent one at the top, so the noun ends in a vowel.

4. How is 책이 said?

Show answer

[채기]: the final ㄱ moves across to the silent ㅇ.

5. Which particle goes on the question word in 누__ 와요? (Who is coming?)

Show answer

가: 누가 와요? Question words as subject take 이/가.

6. Make "I'm the one who drinks it" with 저 and 마셔요.

Show answer

제가 마셔요. (jega masyeoyo.) 저 becomes 제 before 가.

7. Which particle fits: 저__ 학생이에요. (introducing yourself)?

Show answer

는: 저는 학생이에요. Introductions use the topic particle.

8. Say "There is a cat" and "As for the cat, it sleeps". Which uses 이/가 and which 은/는?

Show answer

고양이가 있어요. (new information, 가) and 고양이는 자요. (known, being talked about, 는).

9. Can you write 친구는가 (both particles on one noun)?

Show answer

No. A noun takes the topic or the subject marker, not both.

10. What is the difference in feeling between 물이 차요 and 물은 차요?

Show answer

With 이: you notice and report that the water is cold. With 은: you are talking about the water (or contrasting it with something else) and say it is cold.

Coming up in Chapter 4: Object, Place and Direction Particles. You will meet 을/를, 에, 에서, 으로, 와/과 and 도, and use the same vowel-or-consonant test you learned here.