Plain forms and honorific forms in Korean language

Although we put ~요, it is not polite enough when you talk to elderly or someone is higher than you in your company.

Plain forms		Honorific forms
이름 name	이름이 뭐예요? What is your name?	성함 name	성함이 어떻게 되세요? What is your name?
나이 age	나이가 몇  살이에요? How old are you?	연세 age	연세가 어떻게 되세요? How old are you?
생일 birthday	오늘은 친구 생일이에요. Today is my friend’s birthday.	생신 birthday	오늘은 할아버지 생신이에요. Today is my grandfather’s birthday.
자다 To sleep	아기가 자요. A baby is sleeping.	주무시다 To sleep	어머니가 주무세요. My mother is sleeping.
먹다 To eat	동생이 아침을 먹어요. My younger sis/brother is eating breakfast.	드시다 To eat/drink 잡수시다 To eat	아버지가  차을 드세요. My father is drinking the tea. 아버지가 점심을 드세요. My father is eating lunch.
있다 Have/exist/stay	동생이 집에 있어요. My younger sis/brother is at home.	계시다 Have/exist/stay	어머니가 집에 계세요. My mother is at home.
말하다 To speak/talk	친구가 말해요. My friend is talking	말씀하시다 To speak/talk	선생님이 말씀하세요. The teacher is talking.
죽다 die	그 남자가 죽었어요. That man died.	돌아가시다 die	할아버지가 돌아가셨어요. My grandfather passed away.
배고프다 hungry	저는 배가 고파요. I am hungry.	시장하시다 hungry	할머니가 시장하세요. My grandmother is hungry.
아프다 Be sick	동생이 아파요. My younger sis/brother is sick	편찮으시다 Be sick	할머니가 편찮으세요. My grandmother is sick.
주다 To give	동생한테 케이크를 줘요. I give a cake to my younger sis/borhter.	드리다 To give	할머니께 케이크를 드려요. I give a cake to my grandmother.

Plain nouns	Meaning	Honorific form-nouns
아들	son	아드님
딸	daughter	따님
이/가 (한테)	Subject particle / to	께
집	house	댁

So, Greetings are honorific forms.

많이 드세요. (Please eat more)

안녕히 주무세요. (Good night)

손님, 말씀하세요. (Customer, please speak)