What is なん in そうなんですか


I understood roughly what sou desu, sou des ka mean. But I'm having difficulty
in understanding the word nan in sou nan des ka. If Sou des ka can literally
be translate as "correct/it seem so is it?" How does adding nan "what" fit in
this sentence? If anyone could explain would be much appreciated.




This なん is not 何; this is な + んです + か。

そう is treated like (but it's really not) a na-adjective. So following the
construction [here](https://jlptsensei.com/learn-japanese-
grammar/%E3%82%93%E3%81%A7%E3%81%99-ndesu-%E3%82%93%E3%81%A0-nda-meaning/), it
becomes そうなんですか。From the same website:

> んです (ndesu) has the same meaning as です (desu), but is different in that it
> feels a bit more personal since it is used to explain something, give
> reasoning, or to emphasize something.

So corollarily, そうなんですか is like そうですか but it feels a bit more personal.

(Note: I believe this has already been answered somewhere in this site, but
I'll answer it anyway for good measure.)




This なん is not 何; this is な + んです + か。

そう is treated like (but it's really not) a na-adjective. So following the
construction [here](https://jlptsensei.com/learn-japanese-
grammar/%E3%82%93%E3%81%A7%E3%81%99-ndesu-%E3%82%93%E3%81%A0-nda-meaning/), it
becomes そうなんですか。From the same website:

> んです (ndesu) has the same meaning as です (desu), but is different in that it
> feels a bit more personal since it is used to explain something, give
> reasoning, or to emphasize something.

So corollarily, そうなんですか is like そうですか but it feels a bit more personal.

(Note: I believe this has already been answered somewhere in this site, but
I'll answer it anyway for good measure.)

