Hello mtothealcolm,
It's nice to meet you and thank you for joining us at KC101. I am George, a fellow student here. My input is often less than perfect but I hope sharing my meager understanding will help you and me learn more Korean. Also my input sometimes serves as a platform from which our excellent KC101 teachers can elaborate.
OK, about:about
As you know, about has several definitions in English, it looks like you are interested in the meaning "regarding" or "concerning" (rather than 'almost' or 'near'), so you may have a hard time finding that definition in a English-Korean dictionary.
about (regarding/concerning) - ~에 관하여, ~에 대하여 these two are almost interchangeable with little difference in meaning, so you can usually use the pattern 'something에 곤하여' 관해서, 관한 etc.
First let's look at "무슨 말이야?"
actually I know this one. 무슨 말이야
but the word 'about' doesn't seem to be in it.
When you say 'I know this one' you probably translate it something like 'What are you talking
about?' And you are correct when you say 'the word 'about' doesn't seem to be there.' In fact, a word meaning 'about' or 'regarding' is conspicuously absent although the meaning 'talking about' can be read into it. This little (somewhat rude) sentence 무슨 말이야? literally translates 'What talk is it?' - 'What are you saying?' and can also (depending on situation/intonation) mean "I don't understand" - "I can't believe/accept that!"
so is it per situation that I need to learn, and I should just forget about translating 'about' into korean?
Ha ha - yeah there are a lot of 'per situation' in Korean but I think you can accomplish an effective translation of 'about' in most cases
examples:
this book is about lions and tigers.
이것은 사자와 호랑이
에 관한 책이에요 alt: 이책은 사자와 호랑이
에 대한 거에요.
Neither of the above two translations is natural, but I have chosen more literal translations to illustrate 'about'
I don't care about money.
난 동
에 대해서 상관없어요 -indifferent toward. 난 돈에 대해서 신경을 쓰지 않아요 -not one to worry about. (next example 'about' is missing but we can still translate the same way)
난 돈하고 상관없어요 -I don't care about money.
what are you talking about? -a literal translation sounds a bit odd to me but here you go... 무엇
에 대하여 이야기 하는 거에요? 무엇
에 대해서 이야기 하는 거에요?