LEARN KOREAN (한국어) [GRAMMAR] #1

~는/은 AND ~이/가 REVISITED (AGAIN)

Now that you have continued to increase your understanding of Korean grammar over the past few lessons – and specifically learned how to ask questions in Korean, I can continue to explain the nuances between ~이/가 and ~는/은.

Assuming that the situation is not set up in a way that would be grammatically appropriate to compare yourself with somebody else, it would be very awkward for you to say the following:

내가 밥을 먹었어

If you just walked into a room without anybody saying anything to you, or without any prior back-story, and simply said "내가 밥을 먹었어" (despite being able to understand you perfectly) it would sound very awkward to Korean people.

When you use ~이/가 over ~는/은, the speaker is putting an enormous amount of stress on the fact that it was that particular subject that did the action. The speaker isn't comparing anything, but specifically stressing that it was the subject who/that does the action in the sentence (or has the properties described by the adjective, or "is" the thing attached to 이다). Again, this is just a nuance, and cannot be expressed in translation to English. The only way it can be explained is through descriptions.

The reason why "내가 밥을 먹었어" sounds weird is because it is just like walking into a room and saying:

"I am the one who ate rice!"
Note here that I wouldn't actually translate "내가 밥을 먹었어" to "I am the one who ate rice." I would still translate it to "I ate." I am using the translation "I am the one who ate" to show how the stress can be on the subject.
Nobody would ever say that without anything prompting a person to say it. Instead, you would just say:

나는 밥을 먹었어 - I ate rice
Note that here, you are not comparing anything. You are also not stating a general fact. You are just indicating the subject of the sentence. How can I know that nothing is being compared? How can I know that this isn't just a general fact? How can I know that ~는/은 is just acting as a plain old subject marker?

I am going to reiterate what I said in previous lesson:
This is precisely what causes the confusion amongst foreigners when trying to distinguish the difference between ~이/가 and ~는/은. Both of them can be used to express more than one nuance. The only way you can distinguish between the particular nuances being used is by understanding the situation in which they are used.

The whole process of distinguishing ~이/가 from ~는/은 is incredibly confusing. I want to share an important phrase that I came up with that you should always think about when trying to learn the purposes of these particles:
"It's not about understanding them – it's about understanding when to use them."

At this point I would like to dive a little bit deeper into this purpose of stressing the subject of a sentence. Like I said, to have this purpose, it would need some sort of back-story indicating why the speaker would need to stress the subject.

It would be weird in most situations to just say the following as a one-off sentence:

내가 학생이야
... this is just like walking into a room and saying "It is me who is a/the student!"

However, imagine two students in a class arguing about who gets to sit in the front row (the best seats in the class). After arguing for a few minutes, the class president can come in and say:

내가 반장이야! - I am the class president! (반장 = class president)

In this situation, the speaker is stressing that it is he/she that is the class president, and therefore has the power to solve the situation.

I waited until this lesson to talk about this usage because now you know how to ask questions. The particle ~이/가, in its usage as a subject stressor, is used when somebody specifically asks "who" did a particular action.