Topic vs Subject: The Core Distinction
Korean has two sets of particles that English does not distinguish: topic particles (은/는) and subject particles (이/가). Understanding the difference is essential to sounding natural in Korean.
| Particle | Name | Function | Think of it as... |
|---|---|---|---|
| 은/는 | Topic marker | Marks known/old information, sets the topic, or creates contrast | "As for X..." |
| 이/가 | Subject marker | Marks new information, identifies the subject, or answers "who/what" | "X is the one that..." |
Choosing Based on 받침 (Final Consonant)
The form of the particle depends on whether the preceding noun ends with a consonant (받침) or a vowel.
| Condition | Topic | Subject |
|---|---|---|
| After 받침 (consonant) | 은 | 이 |
| After vowel (no 받침) | 는 | 가 |
Examples by Ending
| Noun | Ends with | Topic | Subject |
|---|---|---|---|
| 사람 (person) | ㅁ (받침) | 사람은 | 사람이 |
| 동물 (animal) | ㄹ (받침) | 동물은 | 동물이 |
| 음악 (music) | ㄱ (받침) | 음악은 | 음악이 |
| 고양이 (cat) | vowel | 고양이는 | 고양이가 |
| 강아지 (puppy) | vowel | 강아지는 | 강아지가 |
| 영화 (movie) | vowel | 영화는 | 영화가 |
When to Use 은/는 (Topic)
Use 은/는 when:
- Setting the topic (what the sentence is about):
-
한국어는 재미있다. — "As for Korean, it is fun."
-
Referring to known/old information:
- A: 저 사람은 누구예요? — "Who is that person?"
-
B: 저 사람은 선생님이에요. — "That person is a teacher."
-
Making a contrast:
- 고양이는 좋다. (But dogs, not so much.) — "Cats, I like."
When to Use 이/가 (Subject)
Use 이/가 when:
- Introducing new information:
-
날씨가 좋다. — "The weather is good." (I'm telling you something new)
-
Answering "who" or "what" questions:
- Q: 누가 학생이에요? — "Who is a student?"
-
A: 나가 학생이에요. — "I am a student." (I'm the one)
-
Something exists or happens for the first time in the conversation:
- 고양이가 있다. — "There is a cat."
Side-by-Side Comparison
| Korean | Particle | Nuance |
|---|---|---|
| 나는 학생이다. | Topic | "As for me, I am a student." (talking about myself) |
| 나가 학생이다. | Subject | "I am the student." (I'm the one, not someone else) |
| 날씨는 좋다. | Topic | "As for the weather, it's good." (maybe other things aren't) |
| 날씨가 좋다. | Subject | "The weather is good." (new observation) |
Common Patterns
With Question Words
Question words like 누구 (who), 뭐 (what) always take 이/가, never 은/는:
| Korean | English |
|---|---|
| 누가 왔어요? | Who came? |
| 뭐가 좋아요? | What is good? |
With 있다/없다
Existence verbs (있다/없다) typically use 이/가:
| Korean | English |
|---|---|
| 고양이가 있다. | There is a cat. |
| 사람이 없다. | There is no person. |
Practice
Try adding the correct particle (은/는 or 이/가) to these sentences:
- 영화___ 재미있다. (The movie is fun — you're setting the topic)
- 강아지___ 귀엽다. (The puppy is cute — new information)
- 음악___ 좋다. (Music is good — setting the topic)
- 누___ 왔어요? (Who came?)