은/는 and 이/가 are definitely a difficult concept to understand, and that’s partly due to the fact that English doesn’t have particles like these. The best comparison would be to compare these particles to how we might place emphasise, or stress parts of a sentence to convey a concise connotation.

However, let me first summarise and then I will delve into an explanation.

은/는 (Topic Marking Particles)

은/는 have the nuance of “As for” or “In regards to”. These are used to:

Mark the topic (Inform the listener what it is you are talking about, or what you are about to talk about.)

Introduce a new topic

Contrast information (Place emphasise on the topic in regards to other information in a sentence.)

이/가 (Subject Marking Particles)

이/가 are essentially a softer, and more neutral form of emphasise. They can have the nuance of “None other than” or “Nothingbut”. These are used to:

Mark the subject of the sentence. (Usually the noun; the whatever, or whomever is performing an action or being described in a sentence.)

Express opinion and answer questions. (Places emphasise on the subject of a sentence to form a clear opinion or answer.)

How do they differ?

In a very simple explanation, 은/는 place strong emphasise but they are more concerned with the ACTION of the sentence (The verb, the adjective etc). Whereas 이/가 provide soft emphasise on the subject and they are more concerned with the WHO of the sentence.

Explanation

Marking the Topic and Subject of a Sentence (and placing emphasise).

은/는 mark the topic of the sentence so that the listener can understand what it is that the speaker wants to ‘emphasise’.

학생은 책을 읽어요. (The STUDENT is reading a book)

In this sentence, 은 has marked the student as the topic. Therefore, the listener can conclude that it is non-other than the student that is reading the book. This sentence has the nuance of “As for the student” or “In regards to the student”. In English, we would stress the word student to grab the same effect. However, this sentence also wants to place interest on the verb ‘to read’.

학생이 책은 읽어요. (The student is reading a BOOK)

Whereas in this sentence, 은 has indicated that the book is the topic. In this case, the sentence has placed emphasise on the fact it is a BOOK that the student is reading, and not a magazine or the newspaper. We would emphasise the word BOOK in English to establish the same effect. Notice how since the topic is now the BOOK, the STUDENT is now the subject.

학생이 책을 읽어요

Finally here, you’ll notice how the subject particle is a softer emphasise of the word ‘student’. This sentence is entirely focused on the fact that it is the STUDENT who is reading a book. It has the nuance of “None other than the student, is reading a book”.

It is important to understand that in everyday conversation, these 은/는 particles are regularly dropped since it is unusual to use them in every sentence, but they are imperative when they are used to contrast information.

Contrasting Information

은/는 also like to strongly emphasise or contrast the topic in regards to the information in a sentence.

오늘 날씨 좋네요.

This sentence is merely a statement. It simply implies, “The weather is good today”.

오늘은 날씨 좋네요.

Whereas this sentence has marked TODAY as the topic, which has the nuance of “As for today, the weather is good.” This implies that the weather hasn’t been good recently, but TODAY the weather is good. This is a good example of how the topic particle is acting to contrast information.

 오늘 날씨는 좋네요.

This sentence has marked the WEATHER as the topic, so here, it is implying how “Today, at least the weather is good.” So essentially, the particle is expressing how other things might not be good today, but at least the WEATHER is good.

That’s how powerful these particles 은/는 can be.

Introducing a New Topic.

은/는 are also an important, concise and clear way to introduce a new topic. Remember, 은/는 have the nuance of “As for” or “In regards to”.

이거 커피예요. This is coffee. (This thing is coffee)

이거는 물이에요. This is water. (AS FOR THIS, it is water / The other thing was coffee, but THIS ONE is water.)

이거는 사과예요. This is an apple. (AS FOR THIS, it is an apple / The other things were not apples, but THIS ONE is an apple.)

이거는 오렌지주스예요. This is orange juice. (AS FOR THIS, it is orange juice / Everything else mentioned so far was not orange juice, but THIS ONE is orange juice.)

Once a topic has been established, the topic particles are generally no longer required unless you want to change the topic.

Expressing Opinion and Answering Questions. (Soft emphasise)

이/가 also like to place emphasise, but like I mentioned before, it is a softer emphasise like in the 학생이 책을 읽어요 example. Specifically, 이/가 are used when concerned with WHO did something or WHAT did something:

고양이가 자요. The CAT is sleeping. (None other than the CAT is sleeping.)

내가 샀어요. I bought (it). (It was ME that bought it.)

But alongside this, the subject particles are a great way to emphasise an opinion. They can add more flavour to a sentence, and express WHICH ONE, WHO, and WHAT more concisely in a sentence.

“ABC 좋아요.”

Here the sentence is implying that ABC is good. But if you disagree and think that XYZ is better, then you can use 이/가 to place emphasise on the SUBJECT (Which, who, what) that you find better.

ABC 좋아요? XYZ가 좋아요!

Here, the subject particle is emphasising how you find XYZ better than ABC. It is clearly indicating your opinion by placing soft emphasise.

Similarly, 이/가 are a great way to answer a question since they indicate the subject of a sentence without changing the topic!

뭐가 가장 좋을 것 같아요?

This sentence is expressing curiosity as to WHAT would be the best?

이게 가장 좋을 것 같아요. (게 is a casual, shorter way to say 것이.)

In the is sentence, the subject particle has attached to the word ‘this’ to indicate an opinion that THIS is best. This sentence has the nuance of, “I think THIS would be best”. 

You can not use 은/는 in your reply without sounding awkward since it would sound like you are trying to change the question. Because remember, 은/는 are used to change the topic!

However, this can get a little complicated in situations when the question is concerned with the WHAT someone or something did. Since these questions are more interested in WHAT is was you or someone did, 은/는 are used since they place more emphasise on the ACTION of a sentence. But in general, the speaker already knows WHO it is they are asking about, so it’s obvious that they are more interested in WHAT that person did!

For example, if someone asked WHO ate? You could say 제가 먹었어요. Since the question is concerned with WHO did something. 

But if they asked WHAT did you do at the shopping mall? You could say 저는 구두를 샀어요 because the speaker already knows it was YOU who went, and they are curious about WHAT it is you did.

Confusing? Yes. But don’t worry, the more you try to break down the roles into small pieces, the more you will begin to understand. Just try to be more observant when reading and notice where each of these particles is used. It is definitely not something you are expected to know quickly, but it is something you pick up along the way! Don’t stress over them, and just take your time.

That’s the basics! I think for now that will conclude this post. There’s also the issue about using them both in the same sentence, but this post should hopefully give you a better understanding what their roles are! If you would like me to further my explanation, just let me know. And of course if you have any other questions, feel free to ask!

Bran:

Many of the elaborate background “sets” from the original Star Wars trilogy were actually just detailed oil paintings on panes of glass. Source Source 2 Source 3

when you think you’re real cool, but you’re ain’t cooler than snsd, so… it’s…