Let's learn about "용건이 뭐죠?"

용건이 뭐죠? = 용건이 무엇이에요? : What do you want?

[other expressions]

<반말(talking down to)>

- 용건이 뭐니? (to younger people or friends)

- 용건이 뭐냐? (to younger people or friends)

- 용건이 뭐야? (to younger people or friends)

- 용건이 뭐지? (to younger people or friends)

- 용건이 뭔가? (to younger people or friends)

- 용건이 뭔지? (to younger people or friends)

- 용건이 뭔데? (to younger people or friends)

- 용건이 무엇이니? (to younger people or friends)

- 용건이 무엇이냐? (to younger people or friends)

- 용건이 무엇이야? (to younger people or friends)

- 용건이 무엇이지? (to younger people or friends)

- 용건이 무엇인가? (to younger people or friends)

- 용건이 무엇인지? (to younger people or friends)

- 용건이 무엇인데? (to younger people or friends)

<존칭/존댓말/높임말/경어(honorific)>

- 용건이 뭐지요? (honourific by '-요')

- 용건이 뭐죠? (honourific by '-요'; -죠? is a short form of -지요?")

- 용건이 뭔가요? (honourific by '-요')

- 용건이 뭔지요? (honourific by '-요')

- 용건이 뭔데요? (honourific by '-요')

- 용건이 뭐예요? (honourific by '-요')

- 용건이 뭡니까? (formal; honourfic by '-ㅂ')

- 용건이 뭐세요? (more honourific by '시-')

- 용건이 뭐셔요? (more honourific by '시-')

- 용건이 뭐입니까? (more honourific by '시-')

- 용건이 무엇이지요? (honourific by '-요')

- 용건이 무엇이죠? (honourific by '-요'; -죠? is a short form of -지요?")

- 용건이 무엇인가요? (honourific by '-요')

- 용건이 무엇인지요? (honourific by '-요')

- 용건이 무엇인데요? (honourific by '-요')

- 용건이 무엇이에요? (honourific by '-요')

- 용건이 무엇입니까? (formal; honourfic by '-ㅂ')

<극존칭(high honorific; extreme honorific)>

- 용건이 무엇이세요? (more honourific by '시-')

- 용건이 무엇이셔요? (more honourific by '시-')

- 용건이 무엇이십니까? (more honourific by '시-')

[explanations]

* 용건 : [Pronunciation: 용껀] [用件] [=볼일•용무] business; affairs; [=할 일] things to do; an engagement; work; an errand

* -이 : a particle makes 용건 subjective after a word ends in a consonant

* 용건이 : [Pronunciation: 용꺼니]

* 뭐 : a short form of 무엇(what)

* 뭔 : a short form 무슨(what)

- 뭔 일이세요? = 무슨 일이세요? : What's up?

* 어떤 : [=무슨] what / what kind[sort] of / what ‥ like

- 어떤 학교입니까? = 무슨 학교입니까? :  What kind of school is it?

* 이다 : be 

* 뭔데요? : 뭐(what; 뭐 + -ㄴ contracted into 뭔) + 이(the stem of 이다; 이 erased before ㄴ데) + -ㄴ데?(an interrogative verb ending suffix) + -요(an honourific ending suffix)

* 뭐예요? : 뭐(what) + 이(the stem of 이다; 이 + 여 contracted into 예) + -여?(an interrogative verb ending suffix) + -요(an honourific ending suffix)

* 무엇이에요? : 무엇(what) + 이(the stem of 이다; 이 + 어 contracted into 에) + -어?(an interrogative verb ending suffix) + -요(an honourific ending suffix)

* -예요? should be used after a noun ends in a vowel like 뭐

- 이건 뭐예요? : What is this?

* -이에요? should be used after a noun ends in a consonant like 세일 기간

- 세일 중이에요? : Is it on sale?

* 뭡니까? : 뭐(what; 뭐 + ㅂ contracted into 뭡) + -ㅂ니까?(an honourific interrogative verb ending suffix)

* 무엇이세요? : 무엇 + 이(the stem of 이다) + -시(a suffix makes a verb more honourific; -이시 used after a before-letter ands in a consonant) + -어?(an interrogative  verb ending suffix) + -요(an honourific ending suffix)

* 무엇이셔요? : 무엇 + 이(the stem of 이다) + -시(a suffix makes a verb more honourific; 시 used after a before-letter ands in a consonant) + -여?(an interrogative  verb ending suffix) + -요(an honourific ending suffix)

* 무엇입니까? : 무엇 + 이(the stem of 이다) + -ㅂ니까?(an honourific  interrogative  verb ending suffix)

* 무엇이십니까? : 무엇 + 이(the stem of 이다) + -시(a suffix makes a verb more honourific: 이시 used after a before-letter ands in a consonant) + -ㅂ니까?(an honourific  interrogative  verb ending suffix)

* 뭐세요? : 뭐 + 이(the stem of 이다; this omitted) + -시(a suffix makes a verb more honourific; 시 used after a before-letter ands in a vowel) + -어?(an interrogative  verb ending suffix) + -요(an honourific ending suffix)

* 뭐셔요? : 뭐 + 이(the stem of 이다; this omitted) + -시(a suffix makes a verb more honourific; 시 used after a before-letter ands in a vowel) + -여?(an interrogative  verb ending suffix) + -요(an honourific ending suffix)

* 뭐입니까? : 뭐 + 이(the stem of 이다; this omitted) + -시(a suffix makes a verb more honourific: 시 used after a before-letter ands in a vowel) + -ㅂ니까?(an honourific  interrogative  verb ending suffix)

* a noun + -(이)니? / -(이)냐? / -(이)야? / -인가? / -ㄴ가? / -인지? / -ㄴ지? / -(이)지? / -(이)ㄴ데: a questioning form of 이다

* a noun + -인가? / -ㄴ가? / -인지? / -ㄴ지? / -(이)지? / -(이)ㄴ데 + -요 : an honourific ending suffix

* a noun + -예요? / -이에요? / -입니까? / -이세요? / -이셔요? / -이십니까? : an honourific questioning form of 이다 by '-요' / ‘-ㅂ' / '시-'