chinabiz wrote:Thanks, Chris
And so, those following are all OK?
누구이다? (impolite, and seldom used, right?)
Although this construction can occasionally be used to ask questions, in 98% of cases, it's just going to sound wierd using 누구다? to ask the question. As such, 누구야? is going to be a better term and used very often.
누구입니까? (very formal, and most often in written form, is it?)
While this is formal, you'll hear it a lot in certain contexts of spoken language. As you listen to Korean more, and especially if you go to Korea, you will start to get a sense of how/when to use the honorifics and "formal" language such as this. Keep in mind you will often hear 누굽니까? instead.
누구이십니까? (most formal and respect[by 시 & ㅂ니까])
As I said, this construction is used more often in everyday speech than you'd think, and you'll probably read it/hear it as 누구십니까? instead. Typically, just as 누구이세요? becomes 누구세요, you'll often see the 이 left out--except in cases of 누구입니까 in which it's usually left in to alleviate confusion, but when speaking it fast, the 이 is often drowned out anyway in this case.
누구예요? (oral, while polite but no so much)
This is common and polite, but you're just not adding 시 for the honorific--similiar to 누구세요?
누구세요? and 누구셔요? are both right and they both developed themselves from 누구예요? while 누구세요? is most often used?
Finally, I'm not so sure about how 셔요 comes out, is it just another form of 세요?
They're essentially the same thing, but 누구세요 is a more modern form
While it's important to understand the spelling and articulation differences between the different constructions, it's also very important to gague how they are used. It's kind of impossible to say "this is only used in writing." Although Korean construction and articulation often varies between written and spoken form, it's important to understand how each of the forms are used in daily life, the differences between male and female Korean speech, and the natural situations in which to use certain forms. There are a couple research papers on how women use different forms than that of men in certain situations. --- This is not really something you can study per se, but as you read different types of works and watch Korean TV shows, dramas, etc, it will become a lot more apparent.