Let’s look at this common language pattern in Korean.

Words

나 - I , me ( Pronoun )

내 - my ( Pronoun )

저 - I , me ( Pronoun )

제 - my ( Pronoun )

Phrases

나는 한국언니야 - I'm Korean Unnie. ( Informal casual )

내 책이야 - It's my book ( Informal casual )

내 강아지 동동이 - My puppy dongdong ( Informal casual )

내 핸드폰 - My handphone ( Informal casual )

나 좋아해? - Do you like me? ( Informal casual )

저는 한국언니예요 - I am Korean Unnie. ( Informal polite )

저는 한국언니입니다 - I am Korean Unnie. ( Formal polite )

제 책입니다. - This is my book ( Formal polite )

이것도 제 책입니다. - This is also my book ( Formal polite )

저를 구독해주세요 - Please subscribe to me ( Honorific (시) )