-이/가The particle -이/가 (-이 for when the preceding word ends with a consonant and -가 for when the preceding word ends with a vowel) attaches directly to a noun and marks that noun as the grammatical subject of the sentence. If you aren’t familiar with that concept, the subject is the doer of verb, or the person or thing carrying out a certain state in the sentence. For example:She is crying.In this sentence, “she” is the one doing the action. “She” is the doer in this sentence, so it is the subject. Let’s look at another example:The bag got dirty.Being dirty isn’t exactly an action, but the thing in that state is the bag. English does not have any special element marking “she” or “bag” as the subjects of their respective sentences, but Korean does. Let’s translate the above sentences into Korean and make sure we mark the subjects.She is crying. -> 그녀가 울고 있어요.Here, we attach -이/가 to the noun we want to mark as the subject. In this case, the noun is “그녀 (that lady).” Since it ends with a vowel, we choose -가 instead of -이.The bag got dirty. -> 가방이 더러워졌어요.Since 가방 ends with a consonant, we use -이 as our subject particle.Let’s check out some more examples of -이/가 usage:•누가 왔어요? (Who came?) •NOTE: 누가 is the question word 누구 (who) + -이/가!•휴지가 없어요. (There is no toilet paper.)•책상 위에 사과가 있어요. (There is an apple on the table.)•리모콘이 안 돼요. (The remote doesn’t work.)-을/를Next, we have the direct object particle -을/를. Like the subject particle -이/가, it attaches to nouns. Use -을 when the noun ends with a consonant and -를 when the noun ends in a vowel. The direct object is the receiver of the action that the subject does. Let’s take a look:I ate an apple.Here, the apple is receiving the action of being eaten.My younger brother often reads books.In this case, the books are receiving the action of being read.Let’s translate them to Korean!I ate an apple -> 제가 사과를 먹었어요.You can see I used -를 since 사과 ends with a vowel. I also marked the subject with the subject particle -가.My younger brother often reads books. -> 우리 동생은 책을 많이 읽어요. (NOTE: In Korean, 우리 [our/we] is used to mean “my” when referring to family members.)Since 책 ends with a consonant, I used -을. 동생 is the subject of the sentence, but I marked it with the topic particle, which we will see below.Let’s finish up with a few more examples:•미나가 잠을 잘 잤어요. (Mina slept well.) •NOTE: In Korean, one says they “sleep a sleep (잠을 자다).” Similar verbs include “to dance (춤을 추다)” and “to dream (꿈을 꾸다).”•민호 씨가 빵을 먹어요. (Minho eats bread/ Minho is eating bread.) •NOTE: Simple present tense in Korean can be translated as either simple present or present progressive tense in English. -은/는And now we get to the hard part… -은/는! This particle sometimes pops up where you would expect to see the subject particle, and sometimes it shows up where you would expect to see the direct object particle. So, what exactly is this mysterious thing??-은/는 is a topic particle, which means, among other things, that it is used to mark the topic, or focus, of the sentence. This usage often turns up when you want to introduce a new topic or change from one topic to another. Sometimes it helps to translate it as, “as for…”Let’s look at some examples, using -은 when it attaches to a word ending with a consonant and -는 when it attaches to a word ending with a vowel.•저는 미국인이에요. ([As for me,] I’m an American.)•그 배우는 정말 유명해요. ([As for that actor,] That actor is really famous.)•사과는 제가 가장 좋아하는 과일이에요. ([As for apples,] Apples are my favorite fruit.)-은/는 can also be used for showing contrast between things:•민수 씨는 사과를 싫어하지만 저는 사과를 좋아해요. (Minsu hates apples but I like apples.)•서현 씨는 키가 작은 반면에 서현 씨의 여동생은 키가 커요. (Seohyeon is short; on the other hand, her younger sister is tall.) •NOTE how we have both the topic particle and subject particle in the same sentence!•넌 거의 아무거나 잘 먹는데 당근은 왜 안 먹어? (You eat almost anything well, but why don’t you eat carrots?) •We actually have two -은/는 here with different meanings. The first one is 너 + 는 (shortened to 넌) to mark that the speaker wants to focus on this particular person. The second, which we can find on 당근, emphasizes the contrast between the listener eating pretty much everything with the special exception of carrots.•Also notice that the topic particle on 당근 is replacing the direct object particle -을/를!At the end of the day, the usage of -은/는 is one that is best grasped through exposure to native speech. The more Korean you hear, the more you’ll develop your intuition of when you should and shouldn’t use -은/는. However, I hoped this short section on it at least helps you to understand how it functions when you do happen across it.