Asking questions/ でしょ/ のです

[Rinilex]

I'm a bit confused about when to use these, why they're used and the level of formality involved.

1) When asking a question, what's the difference (and which is more formal than the other) among these:
知っているか？
知っているのか？
知っているのですか？
知っていますか？
知っていますのですか？
(And apparently ーますのか isn't used...?)

I've heard that －るか can be seen as rude/ blunt, but as for the rest, I'm not sure if there's a major difference or why you'd use one over the other. The order I put them in is what I've perceived as least formal to most formal (please correct me if I'm wrong.) Is there a massive difference?

In fact, I'm sort of confused as to のです by itself. You can put it with past verbs too, and I'm guessing here it's a politeness thing again - but why (random example) would you say 見たのですか over 見ました(のです)か or something else? When not used in a question - say with an adjective - does it add anything? Is のです any different from just です?

2) I came across なんでしょ today (unfortunately I can't remember the sentence orz but the translation was given as just "it's a ___." Does it work like ___ なんだ, only it's looking for confirmation?

And what exactly does 何なんだ mean? I think it's usually used in question of some kind, but I don't understand why it's phrased that way... "what what?"

 

[Toritoribe]

Haven't you learned so-called "explanatry の/ん"?

Noun-related particles - Tae Kim's Japanese grammar guide

That's the difference between 知っているか/知っていますか and 知っているのか/知っているのですか.(The last one 知っていますのですか？ is wrong.)

な in ～なんでしょ, ～なんだ, 何なんだ are all the attributive form of the copula だ, thus, なん in 何なんだ is not "what".

 

[Rinilex]

I had learnt "the thing that is..." but I wasn't aware of the explanatory component of it (or rather, the actual specified reason for it in certain cases.) You tend to miss out the technical side of things when you're studying alone and picking it up as you go.
Ah, oops! Thought I'd heard it somewhere... although it does sound rather clumsy.

I see now... as in 'なのです', etc. 何なんだ - 何なのですか - "what is it?"
Thank you for clearing that up!

Edit: Although the "the declarative 「だ」 cannot be used in a question" confuses me, because I've seen だ used several times in questions?

 

[Toritoribe]

For instance?

 

[LewiiG]

For instance?

Maybe stuff like "ここはどこだ?!" Or something? I haven't questioned it before but now seems like a good time to.

 

[Toritoribe]

Ah, I see. Yeah, だ can be used in a question with an interrogative such like いつ, どこ or 誰. Unlike just ここはどこ？, ここはどこだ？ often has a nunace of saying to the speaker themselves, though. だ is usually not used in a situation just to ask the location they are at.
Probably Tae Kim is talking about a yes-no question. だ can't be used in questions such like ここは東京だ？ or すしが好きだ？

 

[Rinilex]

Ah, LewiiG made my point. Thanks.

Yeah, I've seen it in places like "誰だ？！" "どこだ？！" or "何なんだ" in response to someone saying their name.

The "nuance of talking to themselves" definitely fits in with the majority of examples I've heard, though.

 

[LewiiG]

Ah, I see. Yeah, だ can be used in a question with an interrogative such like いつ, どこ or 誰. Unlike just ここはどこ？, ここはどこだ？ often has a nunace of saying to the speaker themselves, though. だ is usually not used in a situation just to ask the location they are at.
Probably Tae Kim is talking about a yes-no question. だ can't be used in questions such like ここは東京だ？ or すしが好きだ？

I see. Thanks also!