One of the most challenging aspects of Korean for learners is understanding the difference between topic markers (은/는) and subject markers (이/가). While both can translate to the subject in English, they serve different grammatical and pragmatic functions in Korean.
Basic Distinction
Subject Marker (이/가): Identifies who or what performs the action Topic Marker (은/는): Establishes what the sentence is about
This distinction doesn't exist in English, which is why it's confusing for English speakers.
Subject Markers: 이/가
Form
- 이 (i) - after consonants
- 가 (ga) - after vowels
Usage
Marks the grammatical subject—who or what does the action or is in the state.
Examples:
- 비가 와요. (Bi-ga wayo.) - Rain comes. / It's raining.
- 비 (rain) is doing the action of coming
- 고양이가 자요. (Goyangi-ga jayo.) - The cat sleeps.
- 고양이 (cat) is doing the action of sleeping
- 꽃이 예뻐요. (Kkochi yeppeoyo.) - The flower is pretty.
- 꽃 (flower) is in the state of being pretty
When to Use 이/가
1. New information or answer to "who/what?"
Q: 누가 왔어요? (Who came?) A: 친구가 왔어요. (My friend came.)
2. Emphasis on the subject
- 제가 했어요. (I did it. / It was me who did it.)
3. Neutral description of states
- 날씨가 좋아요. (The weather is good.)
- 방이 커요. (The room is big.)
4. Existential sentences
- 책이 있어요. (There's a book. / A book exists.)
- 사람이 많아요. (There are many people.)
Topic Markers: 은/는
Form
- 은 (eun) - after consonants
- 는 (neun) - after vowels
Usage
Marks what the sentence is about—the topic of discussion. Often implies contrast or establishes context.
Examples:
- 저는 학생이에요. (Jeoneun haksaeng-ieyo.) - As for me, I'm a student.
- Talking about "me" (as opposed to others)
- 한국 음식은 맛있어요. (Hanguk eumsig-eun masisseoyo.) - As for Korean food, it's delicious.
- The topic is "Korean food"
- 이 책은 재미있어요. (I chaeg-eun jaemiisseoyo.) - As for this book, it's interesting.
- Discussing this particular book
When to Use 은/는
1. General statements or known information
- 사과는 과일이에요. (Apples are fruit.)
- 고양이는 동물이에요. (Cats are animals.)
2. Contrasting with something else
- 저는 커피를 좋아해요. 그런데 친구는 차를 좋아해요.
- (I like coffee. But as for my friend, they like tea.)
3. Establishing what you're talking about
- 제 이름은 민수예요. (As for my name, it's Minsu. / My name is Minsu.)
- 오늘은 월요일이에요. (As for today, it's Monday. / Today is Monday.)
4. Previously mentioned or assumed information
- A: 친구를 만났어요? (Did you meet your friend?)
- B: 네, 친구는 집에 있었어요. (Yes, as for the friend, they were at home.)
Direct Comparison
Example 1: Neutral vs Topic
Neutral (이/가):
- 비가 와요. (It's raining.)
- Simple factual statement
Topic (은/는):
- 비는 와요. (As for rain, it's coming.)
- Implies: "Rain is falling, but maybe other weather phenomena aren't happening"
Example 2: New Info vs Known Info
New information (이/가): Q: 누가 왔어요? (Who came?) A: 친구가 왔어요. (My friend came.)
Known information (은/는):
- 친구는 어제 왔어요. (As for my friend, they came yesterday.)
- The friend is already known; you're providing new info (when they came)
Example 3: Emphasis
Subject emphasis (이/가):
- 제가 만들었어요. (I made it. / It was me who made it.)
Topic establishment (은/는):
- 저는 케이크를 만들었어요. (As for me, I made cake.)
- Implying: maybe others made different things
Multiple Particles in One Sentence
You can use both topic and subject markers in the same sentence:
저는 커피가 좋아요. (Jeoneun keopi-ga joayo.)
- 저는 (as for me - topic)
- 커피가 (coffee - subject)
- "As for me, coffee is good." / "I like coffee."
친구는 한국어가 어려워요. (Chingu-neun hangugeo-ga eoryeowoyo.)
- 친구는 (as for friend - topic)
- 한국어가 (Korean - subject)
- "As for my friend, Korean is difficult." / "My friend finds Korean difficult."
The "Contrast" Nuance of 은/는
은/는 often carries an implicit contrast:
저는 학생이에요.
- Literal: "As for me, I'm a student."
- Implied: "I'm a student (but maybe you aren't)"
이 영화는 재미있어요.
- Literal: "As for this movie, it's interesting."
- Implied: "This movie is interesting (but maybe other movies aren't)"
This contrast isn't always strong, but it's often present subtly.
With Existential Verbs (있다/없다)
Using 이/가 (Neutral)
- 책이 있어요. (There is a book. / A book exists.)
- 시간이 없어요. (There's no time. / Time doesn't exist.)
Using 은/는 (Contrast)
- 책은 있어요. (As for books, they exist. [But maybe something else doesn't])
- 시간은 없어요. (As for time, there isn't any. [But maybe something else exists])
Example in context: Q: 펜이 있어요? (Do you have a pen?) A: 펜은 없어요. 연필은 있어요. (As for pens, I don't have any. As for pencils, I have some.)
Questions
Using 이/가 in Questions
Asking about unknown subject:
- 누가 왔어요? (Who came?)
- 뭐가 있어요? (What is there?)
Using 은/는 in Questions
Asking about a known topic:
- 친구는 어디에 있어요? (Where is your friend? [friend already mentioned])
- 이 책은 얼마예요? (How much is this book?)
Common Patterns
Pattern 1: Self-Introduction
Always use 은/는:
- 저는 학생이에요. (I'm a student.)
- 제 이름은 수진이에요. (My name is Sujin.)
- 저는 미국에서 왔어요. (I came from America.)
Pattern 2: Describing States
Often use 이/가:
- 날씨가 좋아요. (The weather is good.)
- 방이 더워요. (The room is hot.)
- 물이 차가워요. (The water is cold.)
Pattern 3: Likes/Dislikes
Use topic (은/는) + subject (이/가):
- 저는 커피가 좋아요. (I like coffee.)
- 친구는 음악이 좋아요. (My friend likes music.)
Pattern 4: Abilities
Use topic (은/는) + subject (이/가):
- 저는 한국어가 어려워요. (Korean is difficult for me.)
- 동생은 수학이 쉬워요. (Math is easy for my sibling.)
Practical Guidelines
Use 이/가 when:
✅ Answering "who" or "what" questions ✅ Introducing new information ✅ Making neutral observations ✅ Emphasizing who did something ✅ Existential sentences (있다/없다)
Use 은/는 when:
✅ Making general statements ✅ Talking about known information ✅ Contrasting with something else ✅ Establishing the topic of conversation ✅ Introducing yourself or providing your details
Common Mistakes
Mistake 1: Using 이/가 for Self-Introduction
❌ 저가 학생이에요. (WRONG) ✅ 저는 학생이에요. (CORRECT)
Self-introductions always use topic marker.
Mistake 2: Using 은/는 to Answer "Who?"
Q: 누가 왔어요? (Who came?) ❌ 친구는 왔어요. (Sounds like contrast: "Friend came [but someone else didn't]") ✅ 친구가 왔어요. (CORRECT - Friend came.)
Mistake 3: Overusing One Particle
Both particles are essential. Don't default to just one:
- Learn which contexts require which particle
- Pay attention to usage in native content
- Practice both patterns regularly
Practice Sentences
Topic marker (은/는):
- 저는 선생님이에요. (I'm a teacher.)
- 한국은 아름다워요. (Korea is beautiful.)
- 오늘은 추워요. (Today is cold.)
Subject marker (이/가):
- 비가 와요. (It's raining.)
- 누가 왔어요? (Who came?)
- 개가 짖어요. (The dog is barking.)
Both in one sentence:
- 저는 한국어가 재미있어요. (I find Korean interesting.)
- 친구는 영화가 좋아요. (My friend likes movies.)
Understanding 은/는 vs 이/가 takes time and exposure. Focus on the patterns and pay attention to usage in authentic Korean content. With practice, choosing the right particle becomes natural.