📌 나는 vs 내가

‘나’ is a pronoun that means I, my, me. 
‘너’ is a pronoun that means you, your. 
‘은/는’ and ‘이/가’ are postposition particles, but have different uses. 

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🎯 은/는 show the attached word is a TOPIC of the sentence.

🙂 나는 바빠요. (As for me, I am busy.)

In this sentence, the topic of this conversation is me. We’re talking about something about me.

 

🎯 이/가 shows that the attached word is the SUBJECT of the sentence, which responds the predicate(action, situation or describe). 

🙂 내가 바빠요 . (I am busy.)

In this sentence, ’가’ shows that ‘내’ is the subject of the action ’그려요’.

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🎯 ‘나/너’ and ‘내/네’ attaches ‘는 and 가’, because it ends with vowels.  
Grammatically, in 9 parts of speech in Korean,  내/네 are ONLY pronoun which ‘가’ attaches. 
Then what about ’내 것’, ‘네 마음’ etc?

🙂 내 이름은 소피아 입니다(My name is Sophia). 
🙂 네 가방이 하얀 색이야.(Your bag is white).

In these sentences, ‘내, 네’ are not single pronouns. These are shortened words of ‘나+의’ and ‘너+의’. You can exchange with these. 

은/는, 이/가 is very difficult and I am sure that most of the Korean cannot explain which is which, or what is what. Please just keep practice and you are able to catch the difference.

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