I know how to write in Korean/ the hangul. 나 한글 쓸 줄(how to write) 알아.(know)
I know how to read Korean/hangul. 나 한글 읽을 줄(how to read) 알아.(know)
I know how to read and write in Korean. 나 한글 읽고 쓸줄 알아.
I know how to read and write in Korean but I don't understand what does the words mean. 나 한글 읽고 쓸줄 알지만, 뜻은 이해못해
I'm not Korean. I'm not from Korea. 나 한국 사람 아니야(not). 나 한국에서 온 것 아니야.
Will you marry me? 나랑(me) 결혼(marry) 해줄래? ( you can notice that in korean we can omit subject.)
I'm studying the Korean language/Korean. 나 한국어 공부하는(study) 중이야.(~ing)
I'm enjoying studying the language. 나 한국어 공부하는 거 좋아(enjoy, like).
Do you know how to speak in English? 영어할 줄 알아?
Can you understand English? 영어 이해할 수 있어? 영어 알아들어?
I know how to speak in English. 나 영어로 말할 수 있어.(i see, i envy you)
I can understand English. 영어 알아들어.
What's your name? 이름(name)이 뭐야(what?)?
My name is Ara Mae. 내(my) 이름(name)은 Ara Mae 야.
I have 2 younger brothers and 2 younger sisters. 2명의 남동생(younger brother)와 여동생(younger sister)가 있어. (남동생과 여동생이 있어. edited after marbling3's comment)
I am the oldest of the 5 siblings.5남매( siblings) 중 첫째(oldest, first old one)야.
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I wish my answer helps you.