What are Subject Particles 이/가 in Korean and How to Use Them?

이/가 (subject particle) is attached after noun or pronoun to designate it as the subject of the sentence. For words ending a vowel, 가 is added, and for words ending in a consonant, 이 is added.

Example:

이것이 책상입니다. This is a desk.

여기가 학교입니다. Here is a school.

What Are The Differences Between 이/가 and 은/는?

When compared with 은/는, 이/가 is mainly used for the following two functions:

First, 이/가 functions to emphasize the preceding subject in particular:

Example:

A: 누가 음식을 준비할거예요? Who is going to prepare the food?

B：줍호씨가 음식을 준비할거예요. Junho will prepare the food.

Since the “Junho” part is what we are expecting for, so by using 이/가, instead of 은/는, we are actually suggesting that it is Junho, not anybody else, who will prepare the food.

Please compare how 이/가 and 은/는 are used to emphasize different parts in the following sentences:

줍호씨가 음식을 준비할거예요. By using the subject particle 이/가, we are emphasizing the subject “Junho” part.

줍호씨는 음식을 준비할거예요. By using the topic particle 은/는, the emphasis of the sentence is in the “prepare the food” part.

Second, -이/가 is used to introduce new information in a sentence. If we start to talk about something for the first time in our conversation, we can use 이/가:

Example:

저기 민우씨가와요. Minu is coming this way.