Let’s learn about "생일”

오늘 내 생일이야 : Today is my birthday

[other expressions]

- 오늘 내 생일이다. (to younger people or friends)

- 오늘 내 생일이네. (to younger people or friends)

- 오늘 내 생일이야. (to younger people or friends)

- 오늘 제 생일이네요. (honourific by ‘-요’)

- 오늘 제 생일이에요. (honourific by ‘-요’)

- 오늘 제 생일입니다. (formal; honourific by ‘ㅂ’)

[explanations]

* 오늘 : today

* -은 : a time suffix; this omitted

* 내 : a short form of 나의(my; non-honourific word)

* 제 : a short form of 저의(my; honourific word)

* 나 : I (non-honourific word)

* 저 : I (honourific word)

* -의 : a suffix makes 나 / 저 possesive

* 생일 : birthday <— 생(birth) + 일(day)

* 이다 : be

* 입니다 : 이(the stem of 이다) + -ㅂ니다(an honourific descriptive verb ending suffix)

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

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

* a verb + -이에요 / -입니다 : an honourific descriptive form of 이다 by ‘-요’ / ‘-ㅂ’