The particle 何 seems unnecessary.
Here “na” is not a particle but a variation of the copula (“verb”) “da” (plain form of “desu”, “no” can be another variant in other contexts). You must use “na” instead of other variants in some contexts. For example before explanatory “no” (or its variarion “n”) as in this case.
As usual, Tae Kim’s guide explain this quite well:
http://www.guidetojapanese.org/learn/grammar/nounparticles#The_particle_as_explanation
Scroll down to “To express state-of-being…”
You could leave it out but the なん makes the question softer. As mentioned in Tae Kim’s guide, なん/ん can be explanatory but it can also draw attention to something , place emphasis on something. If you use it at the start of an explanation, the listener knows more information will follow.
Niki112, I’m sorry but I’m not convinced by your explanation. According To TK, here you don’t have “nan”, but “na”, What makes the question softer or puts emphasis, as you explain, is the “n desu” part, not the “na” before it, which is OP’s question: s/he is asking whether you need “na”, given that the “n desu” structure is used, not whether you need to add “n desu” in the first place.
To analyze it a bit deeper:
- Base sentence without explanatory extension
Anata wa umare wa Kantou desu ka? - Now you add the explanatory structure no/n desu, if you put them together you’d have:
*Anata wa umare wa Kantou desu n desu ka
That is, of course not correct, you need a plain form before “no”/n, so it should be
*Anata wa umare wa Kantou da n desu ka
But that is still incorrect! Before “no” you must use the variant “na” instead of “da” (o “no”), so finally you get the example sentence
Anata wa umare wa Kantou na n desu ka
A litteral translation would be:
Is it so that (n desu ka) for you the birthplace is (na!!!) Kantou? “Na” here means “is”, equivalent to “desu” in the sentence without “n desu”.
If instead of a noun (Kantou) you’d have a verb you could just leave it in the plain form, as in another example in the same lesson:
どのくらい こちら に 住んで おられる んです か 。
But after a noun in a sentence like this, you do need to add “na”
Hi ftornay,
I am afraid I don’t analyse grammar like that… If you feel that my explanation is lacking/not correct, so be it. I was only talking about なん/ん not about な in itself because to me, な doesn’t stand on its own here.
Then how do you explain sentences with a verb in which you add “n desu” , an “n” without na?
Notice also that you can change “n” into “no” in these sentences, both of the above goes against the idea that here the word is “nan”:
My claim is that whe you want to use “n desu” as an “explanatory structure” the grammar is like this:
- For a verb: put it in plain form and add “n desu” or equivalent (“no”, “no desu”, “no da”, …)
Tabemasu → taberu n desu / taberu no desu, … - For a noun, add “na” then “n desu”
Kore wa o-kashi [desu] → Kore wa o-kashi na n desu / Kore wa o-kashi no desu, …
[first desu changes to “na”, alternative plain form of it]
For example, in this detailed explanation of this structure, the exact same point is made, including the equivalence of “na” to “da”, (as also in TK’s guide). Scroll down to “Japanese Sentences Ended with Noun or Na-adjective”:
I found a wonderful example! This is a video by a native speaker who is also a great teacher and creates very detailed videos. She also usually color-codes sentences for students to better understand the sentence structure. Notice how she colors “na” in one color and “n desu” in another! In this example, as expected “na” follows a noun. Link to the relevant time code:
And here she spells it out, adding color coding and even separating words (and thus “na”) with “plus” signs:
On top of the example sentence:
A bit later she gives an alternative expression with “kara” instead of the explanatory particle and you can see how “na” changes to “da”, even with the same color code, showing how they are variant of the same word.