Korean changes its words and endings to show respect: polite and formal endings, honorific verbs and nouns, and casual speech.
반말
Casual speech (for close friends and younger people)
존댓말
Polite speech
-요
Polite ending (used in most everyday situations)
-습니다/-ㅂ니다
Formal ending (news, work, announcements)
-(으)세요
Honorific ending (shows respect to the person you talk about or to)
가세요
Goes (someone respected goes)
드세요
Please eat (honorific of 먹어요)
드셨어요?
Have you eaten? (honorific)
주무세요
Sleeps (honorific of 자요)
안녕히 주무세요
Good night (to an older person)
계세요
Is (somewhere), honorific of 있어요
말씀하세요
Please go ahead and speak (honorific of 말해요)
말씀
Words, what someone says (honorific)
드려요
To give (to someone respected), humble form of 줘요
할머니께 선물을 드렸어요
I gave my grandmother a present
께서
Subject particle (honorific of 이/가)
께
To (a person, honorific of 에게)
아버지께서 오셨어요
My father has arrived (honorific)
성함
Name (honorific of 이름)
연세
Age (honorific of 나이)
연세가 어떻게 되세요?
May I ask how old you are? (to an older person)
진지
Meal (honorific of 밥)
댁
Home (honorific of 집)
분
Person (honorific of 사람)
저
I (humble form of 나)
저희
We, our (humble form of 우리)
여쭤봐도 될까요?
May I ask you something? (humble)
잠시만 기다려 주세요
Please wait a moment
실례지만
Excuse me, but (a polite opener)
괜찮으세요?
Are you all right? (honorific)
어디 가세요?
Where are you going? (honorific)
선생님, 질문이 있습니다
Teacher, I have a question (formal)
말 놓으세요
Please speak casually to me (said to someone older)
말 편하게 하세요
Feel free to speak casually
우리 말 놓을까요?
Shall we speak casually with each other?
고마워
Thanks (casual, to friends)
미안해
Sorry (casual)
뭐 해?
What are you doing? (casual)
밥 먹었어?
Have you eaten? (casual)
응
Yeah (casual yes)