Particles tell you how a noun works
Korean particles attach to nouns and help show their role in a sentence. English often relies heavily on word order; Korean uses both word order and particles. Learn a particle through a short sentence, rather than trying to assign it one permanent English translation.
Some particles come in two forms chosen by the final sound of the noun. A consonant-ending noun takes 은, 이, or 을. A vowel-ending noun takes 는, 가, or 를. For example, 학생 ends with a consonant while 친구 ends with a vowel.
Topics and subjects
은/는 marks a topic and can also create a contrast. 저는 학생이에요 presents information about me: I am a student. The topic marker is 는 because 저 ends in a vowel. 학생은 uses 은 because 학생 ends in a consonant.
이/가 marks a subject. In 누가 학생이에요? the question asks who is a student. 제가 학생이에요 identifies I as the answer. Notice that 저 + 가 becomes 제가. Topic and subject choices depend on what is already known, what is being emphasized, and the wider conversation, so a beginner rule cannot cover every nuance.
Objects before actions
을/를 marks an object in many action sentences. 밥을 먹어요 means I eat rice or I am eating rice. 한국어를 공부해요 means I study Korean. The verb comes at the end in these examples.
An object particle is not a Korean version of the English word the. It marks the noun’s role. Korean also omits some particles in conversation, but practicing them explicitly helps you understand sentence structure before you meet more casual speech.
A place and an action location
에 often marks a destination or a location with 있어요: 학교에 가요 means I go to school, and 집에 있어요 means I am at home. It also marks a clock time, as in 두 시에, at two o’clock.
에서 often marks where an action occurs: 도서관에서 공부해요 means I study at the library. Compare 집에 있어요 with 집에서 공부해요. These particles have other uses as well, including 에서 for a starting point, but this contrast is a helpful first step.
Practice one decision at a time
First identify the action: eating, studying, going, or being somewhere. Then decide what job the noun has. Is it the thing being eaten, the destination, or the place where studying happens? Finally, choose the particle form that matches the noun’s last sound.
Keep a few accurate model sentences and change one noun at a time. Swap 물 for 커피 in 물을 마셔요 and you get 커피를 마셔요. The meaning changes, but the object’s role remains the same.