이/가: Subject particle

How 이/가 works in real sentences

Picking the form is quick: 이 (i) after a consonant, as in 가방이 gabangi, "the bag", and 가 (ga) after a vowel, as in 사과가 sagwaga, "the apple". The harder question is when to use 이/가 rather than 은/는. Here's what helped me.

Four words change shape

Before 가, these pronouns change, and getting them wrong is the quickest way to sound like a beginner:

• 저 + 가 → 제가 jega, "I" (polite). Never 저가.
• 나 + 가 → 내가 naega, "I" (casual).
• 너 + 가 → 네가 nega, "you". In speech people say 니가 niga so it doesn't sound like 내가.
• 누구 + 가 → 누가 nuga, "who".

It brings in something new

When something first enters the conversation, it usually takes 이/가. Once it's known, it switches to 은/는.

옛날에 공주가 살았어요. 공주는 아주 친절했어요.

yennare gongjuga sarasseoyo. gongjuneun aju chinjeolhaesseoyo.

"Once upon a time there lived a princess. The princess was very kind."

It points at one thing

이/가 picks out exactly who or what. That's why question words take it:

• 누가 왔어요? nuga wasseoyo?, "Who came?"
• 뭐가 좋아요? mwoga joayo?, "What's good?"
• 어디가 아파요? eodiga apayo?, "Where does it hurt?"

And the answer keeps it: 제가 했어요 jega haesseoyo, "I'm the one who did it." With 저는 했어요 jeoneun haesseoyo you'd be saying "well, I did it", which sounds like you're hinting at the others.

Where it's the normal choice

• Having or not having: 시간이 없어요 sigani eopseoyo, "I don't have time." 돈이 있어요 doni isseoyo, "I have money."
• Describing what's happening now: 날씨가 좋아요 nalssiga joayo, "The weather's nice." 목이 아파요 mogi apayo, "My throat hurts."
• Becoming and not being: 의사가 되고 싶어요 uisaga doego sipeoyo, "I want to become a doctor." 저는 학생이 아니에요 jeoneun haksaengi anieyo, "I'm not a student."
• Set phrases: 이해가 안 가요 ihaega an gayo, "I don't get it."

You can still use 은/는 in these when you're contrasting or talking in general: 날씨는 보통 안 좋은데 오늘은 좋아요 nalssineun botong an joeunde oneureun joayo, "The weather's usually bad, but today it's nice." For the side-by-side version, see 은/는 vs 이/가.

With 되다 and 아니다

Two very common verbs take 이/가 on a noun that isn't really the subject. 되다 doeda means "to become", and 아니다 anida means "to not be":

• 의사가 되고 싶어요. uisaga doego sipeoyo "I want to become a doctor."
• 저는 학생이 아니에요. jeoneun haksaengi anieyo "I'm not a student."

English makes you think of these as objects, so learners reach for 을/를 eul/reul:

• ✗의사를 되고 싶어요. uisareul doego sipeoyo
• ✓의사가 되고 싶어요. uisaga doego sipeoyo

Two subjects in one sentence

A sentence can have 은/는 eun/neun and 이/가 at the same time. 은/는 sets up who you're talking about, and 이/가 marks the thing the description is about:

• 저는 사과가 좋아요. jeoneun sagwaga joayo "I like apples." Literally, "as for me, apples are good".
• 토끼는 귀가 길어요. tokkineun gwiga gireoyo "Rabbits have long ears."
• 이 식당은 음식이 맛있어요. i sikdangeun eumsigi masisseoyo "The food at this place is good."

This shape is everywhere with feelings and descriptions, so it's worth getting used to. The 은/는 vs 이/가 comparison has more side-by-side pairs.