**Video pending
I hope you have been keeping your motivation to learn Korean. As I said, it feels difficult at first but that is because our brain is being fed with new information (and a lot of it!).
Learning Korean from a native speaker can often be like learning English from a native speaker (which is not a teacher) as well. While native speakers get all the grammars perfectly well, there is a reason why language teachers are teachers, its because they know how best to explain things. If you ask a native speaker why some things are the way they are, the answer you would probably get is, "its just is".
I'm not a (real) teacher but I would like to share what I found from my self learning when it comes to the above subject. Even for a native speaker they would simply say, "its just is" or 그냥 (keu-nyang).
The question is, if 저 and 나 are 'I/me' and 제 and 내 are 'my/mine' in English, so why are there 제가 and 내가 and why is 저가 and 나가 not used?
If you feel that this is too long to read, you can skip everything and read paragraph*** but you probably will miss some conceptual points. For the inspiring Korean speakers, this may be helpful. Besides pure repetition and practise, understanding concept is best into being able to understand and remember this. In fact, it would be helpful if one can pass it on to other new learners in the future.
For first part of this explanation, if you haven't known, please be a good boy or good girl and study the subject and topic marker from this and this video or just look it up (at the present I don't have a blog post about it, except for the youtube video).
Lets look at whether 'I' is a topic or not. Lets consider the following examples:
1. 저는 민경이에요.
(jo-neun Min-gyeong i-yeyo.)
I am Mingyeong.
2. 저는 배고파요.
(jo-neun bekopayo)
I am hungry.
3. 제가 했어요.
(jega hessoyo)
I did (it).
4. 제가 할게요.
(jega halkeyo)
I will do it (for you).
1. In the first sentence, its an introduction sentence and 저는 and since the person needs to emphasise that his/her name is so and so (and not his friend's, brother's, mother's, etc) - he/she need to make a clear point. Moreover, its normally the first thing you say when you introduce yourself, so first time mentioning 'I' is understandable and then the following sentences can remove 'I' unless its necessary.
The use of 는 topic marker is used because the person speaking is the topic right now. And also it a way of saying, "As for me, I am Minkyeong", as its also possible that the topic before that was about the asker or someone else beside who have already introduced him/herself.
The conversation could have started like "I'm Alex, who are you?" and then answered with "I am Minkyeong" which would have the feeling of "Oh, as for me, I am Minkyeong" (although not said like that).
As a general rule, when you introduce or talk about yourself, you are always the topic thus, topic marker 는 is used.
E.g.:
저는 전이에요 (jo-neun jon-i-yeyo) "I am John."
저는 학생이에요 (jo-neun hakseng-i-yeyo) "I am a student"
저는 미국사람이에요 (jo-neun miguk-saram-i-yeyo) "I am an American"
and etc.
So far, ok? Ok, lets continue...
2. While for the second sentence,
저는 배고파요.
The fact that pronouns are seldom used, this sentence could have just simply sound as
배고파요. Let's say you and your sister sitting studying together and then suddenly you feel hungry, you just say "배고파요!!", its enough to indicate that the person who is hungry is you and not your sister. Thus, pronoun 저는 can be omitted/removed/dropped entirely. In fact, the most you can say about being hungry is you are VERY hungry by just saying "진짜 배고파요!! (I'm really hungry!!), without even mentioning 저는. However 저는 배고파요 is totally acceptable.
In general, saying 'I' or 'me' is perceived as self centric so repeatedly saying 'I' would even more seem like it.
WHY IS IT SO HARD?? Ok, ok, relax, its not that hard...
3. Let's check sentence 3.
제가 했어요.
However if in the case of clearing the air and to emphasis that its a case e.g. someone asks
Q: 이 누가 했어요? (i nuga hessoyo) "Who did this?"
you can confess and say
A: 제가 했어요 (I did it) because "했어요" alone is not clear.
4. Another example is sentence 4.
제가 할게요 (jega halkeyo) - "I will do it for you" and the fact that 할게요 is an action meaning "will do for you" (this is a future grammar lesson), 'you' is more likely the source of the conversation, therefore 'I' is not the topic.
Other examples apply like:-
제가 줄게요 (jega julkeyo) "I will give you."
제가 드릴게요 (jega derilkeyo) "I will give you." honorific form
제가 전화할게요 (jega jon-hwa-halkeyo) "I will (telephone) call (it) for you."
Now, this can be quite confusing especially when you're speaking, there is no time to think what or who is the topic, right?
So, let's make a comparison of two sentences, with 재가 and 저는 but the rest is same.
a. 저는 캐이크를 만들었어요.
(jo-neun khei-kheu-rel mandero-ssoyo)
b. 제가 캐이크를 만들었어요.
(jega khei-kheu-rel mandero-ssoyo)
Both sentences (suppose to) mean "I made (a) cake.
To the simple Kdrama fan, it probably doesn't even matter which is the correct one but the fact that only one of them is correct deserves some investigation.
a. 저는 캐이크를 만들었어요. - this is correct. 'I' is giving a direct statement about him/herself. 'I' is the topic, and the source of the conversation.
b. 제가 캐이크를 만들었어요. - this sentence can be acceptable if it was an answer to
Q: 누가 이 캐이크를 만들었어요? (nuga i khei-kheu-rel manderossoyo) "Who made this cake?' (Now the source of curiosity is the cake, not the cake maker at all).
A: 제가 캐이크를 만들었어요.
But then that will still sound unnatural because 제가 만을었어요 (jega manderossoyo) (I (am the one that) made it) is a more natural response.
Paragraph***
ARE YOU THE SOURCE OF THE CONVERSATION?
This is the general rule; determine the source of the conversation.
If its a statement or description about yourself that you voluntarily give or because you were asked, use 저는 //You are the source of conversation//
If its a statement as a respond to 누가 'who', use 제가 //The source of conversation is an action//
If you are ending with 'ㄹ/를 게요', use 제가. //The source of conversation is the other person//
If either 저는 or 재가 can be omitted, just no need to say it.
Soooo......what are 나는 and 내가?
The rules basically apply except that these are 반말 (intimate speech level) - to be used in intimate situations.
Which brings us back to if 저 and 나 are 'I/me' and 제 and 내 are 'my/mine' in English, so why are there 제가 and 내가 and why is 저가 and 나가 not used?
Answer:
1. 제 is a conjugation of 저 + 의 meaning mine or my while 내 is a conjugation of 나 + 의. Both while meaning my and mine in the polite and intimate level respectively, it has became the accepted variation of 저 and 나.
2.저가 and 나가 technically are grammatically correct but its not used because 제가 and 내가 became the variation that is accepted for the longest time (a long long long long longgg time). It like in English, why do we say 'went' and not 'goed' or 'I am' and not 'I is'. It would be strange if you say "I is Minkyeong" or "I is hungry" isn't it? Its the same for Korean too.
3. 저가 and 나가 probably sound like other words in the Korean language (you could probably look it up) so it would be confusing to use them carelessly.
So, what is 네가?
네가 is intimate for "you" where 너 + 의 is 네 (the sound with 내 is almost same but its either deliberately said to sound 니 or said subtly different but same to the (untrained) foreign ears). 네가 is also an accepted variation like 제가 and 내가.
Its a tongue twister at first, but you'll get it.
So is there 덩신이 and 너는?
Yes. However, you must remember that in Korean language, saying I and you is basically too direct and seems as impolite. People normally are indirect (its kind of like beating around the bush, but in a good way) by using their name or title (see Korean Pronoun Part 1) or just omit it in a clear situation like 누나 예뻐요 or just 예뻐요 for "You look pretty!".
Then, when do we say 저를, 나를, 당신을 and 너를?
을/를 are object markers and used only if nouns have action performed on them like
내가 너를 사랑해. (I love you) - action (verb) is 사라해 and performed on 너, so its I love you.
If you haven't, watch this episode for object markers here.
I hope that helped, kids.
Til then, study smart!