Let's learn about "난 니 편이야"

난 니 편이야 : I'm on your side

[other expressions]

- 난 니 편이다. (to younger people or friends)

- 난 니 편이네. (to younger people or friends)

- 난 니 편이야. (to younger people or friends)

- 전 오빠 편이네요. (honourific by '요')

- 전 오빠 편이에요. (honourific by '요')

- 전 오빠 편입니다. (formal; more honourific by '-ㅂ')

[explanations]

* 나 : I (non-honourific word)

* 저 : I (honourific word)

* 는 : a suffix makes 나 / 저 subjective after a word ends a vowel

* 난 : a short form of 나는

* 전 : a short form of 저는

* 니 / 너 : you (non-honourific word)

* 오빠 : a brother of a girl; a man is older than a woman (honourific word)

* -의 : a particle makes 니 / 너 / 오빠 possesive; this omitted

* 편[便] : (1) a side; a part; a direction; a way (2) a party; a side; a team

* 이다 : be

* a noun + -이다 / -이네 / -이야 : a non-honourific descriptive form of 이다

* a noun + -이네 + -요 : an honourific verb ending suffix

* a noun +  -입니다 : an honourific descriptive form of 이다  by '-ㅂ'