이/가 / 은/는
Subject vs. Topic Marker
이/가 answers 'Who/What did it?'. 은/는 sets the stage, 'As for [this thing]...'
How It Works
Understanding the difference between the subject marker 이/가 and the topic marker 은/는 is a crucial step in learning Korean. While both can sometimes translate to the subject in English, their functions are distinct.
Attachment Rules:
- 이 / 은: Attach to nouns ending in a consonant (e.g., 학생이, 학생은).
- 가 / 는: Attach to nouns ending in a vowel (e.g., 의사가, 의사는).
Key Differences & Usage:
1. New vs. Old Information
- 이/가 is used to introduce new information or identify a subject for the first time. It answers the question "Who?" or "What?".
Example: 옛날에 공주가 살았어요. (Once upon a time, a princess lived.) - The princess is new information. - 은/는 is used when talking about old or known information that has already been introduced.
Example: 그 공주는 아름다웠어요. (That princess was beautiful.) - We are now talking about the princess we just mentioned.
2. Identification vs. Description/General Fact
- 이/가 is used to identify something or someone specific. It puts the focus on the subject itself.
Example: 누가 케이크를 먹었어요? → 제가 먹었어요. (Who ate the cake? → I ate it.) - Identifies 'I' as the one who did it. - 은/는 is used to describe a topic or state a general truth. The focus is on the description or statement that follows the topic.
Example: 사과는 빨갛다. (Apples are red.) - A general fact about apples.
Example: 저는 학생입니다. (I am a student.) - A statement describing myself.
3. Contrast
- 은/는 is very commonly used to show contrast between two or more things.
Example: 영어는 어려운데 한국어는 재미있어요. (English is difficult, but Korean is fun.)
Example: 동생은 키가 큰데, 저는 작아요. (My younger sibling is tall, but I am short.)
In summary, choose 이/가 when you are identifying the specific subject or introducing it for the first time. Choose 은/는 when you are setting a topic to describe, stating a general fact, or making a contrast.
Examples (5)
- 누가 왔어요? 소피아가 왔어요.
Who came? Sofia came.
Word by Word: Who came? Sofia came.
Here, '가' is used to identify the specific person (Sofia) who performed the action. It answers the question '누가?' (who?).
- 소피아는 학생이에요.
Sofia is a student.
Word by Word: Sofia-topic student is.
Here, '는' is used to state a fact or description about the topic, Sofia. We are not identifying her, but describing her.
- 사과는 맛있어요. 그런데 바나나는 맛없어요.
Apples are delicious. But bananas are not.
Word by Word: Apples-topic delicious. But bananas-topic not delicious.
This is a classic example of contrast. '는' is used on both '사과' (apple) and '바나나' (banana) to highlight the difference between them.
- 이것이 뭐예요? 그것은 연필이에요.
What is this? That is a pencil.
Word by Word: This thing-subject what is? That thing-topic pencil is.
In the question, '이' identifies the unknown object. In the answer, '은' is used because the object ('그것') is now the known topic being described.
- 지구는 둥글다.
The Earth is round.
Word by Word: Earth-topic is round.
'는' is used to state a general, universally known fact.
Common Mistakes
Using 은/는 to introduce a subject for the first time.
Different Meaning옛날에 왕자는 살았어요.Better옛날에 왕자가 살았어요.When introducing a character or subject into a story or conversation for the first time, you must use 이/가. After the initial introduction, you can switch to 은/는 to talk about that character as the topic.
Using 이/가 when making a general statement or description.
Different Meaning코끼리가 코가 길어요.Better코끼리는 코가 길어요.This sentence is a general statement about elephants. It means 'As for elephants, their noses are long.' Therefore, the topic marker 은/는 is more natural. The inner clause '코가 길어요' (the nose is long) correctly uses '가' to mark the subject of that clause.
Not using 은/는 to show contrast.
Different Meaning저는 커피를 좋아해요. 제 친구가 차를 좋아해요.Better저는 커피를 좋아하는데, 제 친구는 차를 좋아해요.While the incorrect sentence is grammatically understandable, using 은/는 makes the contrast clear and sound much more natural. '저는' (as for me) contrasts with '제 친구는' (as for my friend).
Learn This First
This comparison helps you understand the differences between 이/가 and 은/는. Study each pattern individually first.
Related Patterns
- 을/를Object Marker
The object marker. While 이/가 and 은/는 mark the subject/topic, 을/를 marks what receives the action of the verb, completing the core sentence structure.
- Core sentence particles
이/가 and 은/는 are two of the most fundamental sentence particles. Understanding them is the first step to understanding how Korean sentences are built.
- Word order basics
The placement of the subject (marked by 이/가) and topic (marked by 은/는) at the beginning of a clause is a key principle of Korean word order.