Learn Hardcore Korean: doseogwane haksaengdeuri isseoyo.

The particle 에 indicates the location where something exists or is located. Since 있다 here means “to exist” or “there is/are,” we use 에 for the place of existence. The particle 에서 marks the location of an action (e.g. 도서관에서 공부해요 “I study at the library”), so it isn’t used with 있다 to express simple existence.

What does 있어요 mean, and what level of politeness is it?

있어요 is the polite informal present form of 있다, meaning “to exist,” “to have,” or “there is/there are.” The -어요 ending makes the sentence polite in everyday conversation. Dropping -요 (i.e. 있어) is casual, and using -ㅂ니다 (i.e. 있습니다) is more formal.

Why do we add 들 in 학생들? Is it always needed to show plural?

The suffix 들 explicitly marks the noun 학생 (“student”) as plural (“students”). In Korean, plurality is often inferred from context, so 들 is optional when the meaning is clear. You’d use 학생들 when you want to emphasize “multiple students.”

Why is the subject marker 이 used after 들, and could we use 가 instead?

Subject markers 이/가 follow nouns: 이 attaches to a noun ending in a consonant sound, and 가 to one ending in a vowel sound. Since 들 ends with the consonant ㄹ, you use 이. You couldn’t swap in 가 here.

What’s the difference between the subject marker 이/가 and the topic marker 은/는? Why is 이 used here?

이/가 marks the grammatical subject, introducing new or neutral information. 은/는 marks the topic, often implying contrast or known information. In 도서관에 학생들이 있어요, we’re neutrally stating “There are students at the library,” so 이 is used. If you said 도서관에는 학생들이 있어요, you’d be making 도서관 the topic and adding slight emphasis or contrast.

Can we omit the particles and just say 도서관 학생들이 있어요?

In very casual spoken Korean, particles are sometimes dropped, but it can sound imprecise or overly informal. For clear and correct polite speech, include both 에 and 이: 도서관에 학생들이 있어요.

Is the word order fixed, or can we say 학생들이 도서관에 있어요?

Korean word order is relatively flexible because particles show each word’s role. You can say 학생들이 도서관에 있어요 or 도서관에 학생들이 있어요 interchangeably; the meaning stays the same, though emphasis may shift.

How would you say “There is one student in the library” in Korean?

You’d change the subject to singular: 도서관에 학생이 있어요. Here 학생 is singular and takes the subject marker 이 after the consonant, so 학생이 있어요 means “There is a student.”