Nouns: Subject Case Marker '가/이'

01

Choosing Between 이 (i) and 가 (ga)

The choice between 이 (i) and 가 (gagagaka) depends entirely on the sound at the end of the preceding noun.

• Ends in a consonant (받침 (pat·chʰimbat·chimpat·ch'impat·chim)): Add 이 (i).
• Ends in a vowel: Add 가 (gagagaka).

This rule helps the sentence flow more smoothly by avoiding the collision of two vowels or awkward consonant clusters.

• 가방이 비싸요.

  ka·bang·i pi·ssa·yo.ga·bang·i bi·ssa·yo.ka·bang·i pi·ssa·yo.ka·pang·i pi·ssa·yo.

  The bag is expensive.

• 모자가 예뻐요.

  mo·ja·ga ye·ppŏ·yo.mo·ja·ga ye·bbeo·yo.mo·ja·ga ye·ppŏ·yo.mo·ca·ka yey·ppe·yo.

  The hat is pretty.

• 학생이 공부해요.

  hak·sæng·i kong·bu·hæ·yo.hak·saeng·i gong·bu·hae·yo.hak·saeng·i kong·bu·hae·yo.hak·sayng·i kong·pu·hay·yo.

  The student studies.

02

Irregular Pronoun Changes

When the subject marker 가 (gagagaka) is attached to certain pronouns, the form of the pronoun changes slightly. These are irregular but very common, so they must be memorized.

• 나 (na) (I, informal) + 가 (gagagaka) becomes 내가 (næ·ganae·ganae·ganay·ka).
• 저 (chŏjeochŏce) (I, formal) + 가 (gagagaka) becomes 제가 (che·gaje·gache·gacey·ka).
• 너 (nŏneonŏne) (You, informal) + 가 (gagagaka) becomes 네가 (ne·gane·gane·ganey·ka).
• 누구 (nu·gunu·gunu·gunu·ku) (Who) + 가 (gagagaka) becomes 누가 (nu·ganu·ganu·ganu·ka).

• 내가 할게.

  næ·ga hal·kke.nae·ga hal·gge.nae·ga hal·kke.nay·ka hal·kkey.

  I will do it.

• 제가 민수입니다.

  che·ga min·su·im·ni·da.je·ga min·su·im·ni·da.che·ga min·su·im·ni·da.cey·ka min·su·im·ni·ta.

  I am Minsu.

• 누가 왔어요?

  nu·ga wass·ŏ·yo?nu·ga wass·eo·yo?nu·ga wass·ŏ·yo?nu·ka wass·e·yo?

  Who came?

03

Usage: Focusing on the Subject

The particles 이/가 (i/ga) are specifically used when the focus of the sentence is on the subject itself. This often happens when answering the question "Who?" or "What?".

If someone asks "Who bought the coffee?", the answer emphasizes the person, not the act of buying. Therefore, you use the subject marker.

• 친구가 커피를 샀어요.

  chʰin·gu·ga kʰŏ·pʰi·rŭl sass·ŏ·yo.chin·gu·ga keo·pi·reul sass·eo·yo.ch'in·gu·ga k'ŏ·p'i·rŭl sass·ŏ·yo.chin·ku·ka khe·phi·lul sass·e·yo.

  My friend bought coffee. (It was my friend, not someone else).

• 비가 와요.

  pi·ga wa·yo.bi·ga wa·yo.pi·ga wa·yo.pi·ka wa·yo.

  It is raining. (Lit: Rain comes).

04

Usage: New Information

When introducing a subject for the first time in a conversation or story, 이/가 (i/ga) is generally used. Once the subject is known to both speakers, subsequent sentences often switch to the topic marker 은/는 (ŭn/nŭneun/nŭnŭn/nŭnun/nŭn) or omit the particle entirely.

• 옛날에 한 남자가 살았어요.

  yenn·ar·e han nam·ja·ga sar·ass·ŏ·yo.yenn·ar·e han nam·ja·ga sar·ass·eo·yo.yenn·ar·e han nam·ja·ga sar·ass·ŏ·yo.yeynn·ar·ey han nam·ca·ka sar·ass·e·yo.

  A long time ago, a man lived.

05

Usage: With Adjectives and Existence

In Korean, adjectives function like verbs (descriptive verbs). When describing a noun using an adjective, or stating that something exists 있다 (it·tait·dait·tait·ta) or does not exist 없다 (ŏp·taeop·daŏp·taep·ta), the subject marker 이/가 (i/ga) is the standard particle to use.

• 날씨가 좋아요.

  nal·ssi·ga cho·a·yo.nal·ssi·ga jo·a·yo.nal·ssi·ga cho·a·yo.nal·ssi·ka co·a·yo.

  The weather is good.

• 물이 차가워요.

  mur·i chʰa·ga·wŏ·yo.mur·i cha·ga·wŏ·yo.mur·i ch'a·ga·wŏ·yo.mur·i cha·ka·wŏ·yo.

  The water is cold.

• 시간이 없어요.

  si·gan·i ŏps·ŏ·yo.si·gan·i eops·eo·yo.si·gan·i ŏps·ŏ·yo.si·kan·i eps·e·yo.

  I don't have time. (Lit: Time does not exist).

06

Difference from Topic Marker 은/는 (ŭn/nŭn)

Learners often confuse the subject marker 이/가 (i/ga) with the topic marker 은/는 (ŭn/nŭneun/nŭnŭn/nŭnun/nŭn). While both can translate to the subject in English, they have different nuances:

• 이/가 (i/ga) (Subject): Identifies the specific subject. Used for new information, specific observations, or emphasizing "which one."
• 은/는 (ŭn/nŭneun/nŭnŭn/nŭnun/nŭn) (Topic): Sets the context. Used for general facts, old information, or making comparisons/contrasts.

• 사과가 빨개요.

  sa·gwa·ga ppal·gæ·yo.sa·gwa·ga bbal·gae·yo.sa·gwa·ga ppal·gae·yo.sa·kwa·ka ppal·kay·yo.

  The apple is red. (Looking at a specific apple).

• 사과는 빨개요.

  sa·gwa·nŭn ppal·gæ·yo.sa·gwa·neun bbal·gae·yo.sa·gwa·nŭn ppal·gae·yo.sa·kwa·nun ppal·kay·yo.

  Apples are red. (General fact about apples).