What does this なのである do in this sentence?


For full context, see here:
<https://www.docdroid.net/5vuuiCe/img-20170821-0002-new.pdf>

The sentence in question (last line): 今、カラオケは単なる機械ではなく、日本が世界中に誇る文化 **なのである** 。

First, my attempt at translation: "Now, Karaoke is not (just) a mere machine
and japan is a culture holding proud in the world."

I just translated the sentence as if なの wasn't present in the respective
phrase because I don't know what to with it here. I also must say that I
wonder wether my interpretation of the second part of this sentence ("Japan
is...") is correct at all. It seems a bit far fetched to me to make Karaoke
representative of the whole japanese culture xD At least this sentence sounds
to me like it does so...^^ That said, maybe japanese people themselves think
so. I don't know, I don't have that much insight into japanese people's heads
:D




The なの is just a case of the "explanatory の" which adds a slight explanatory
nuance to the sentence but doesn't directly affect the meaning much, so it's
fine to leave it out in the translation.

However, I think you're interpreting the grammar of the rest of the sentence a
little wrong. The subject (topic) of the second part of the sentence isn't
Japan - it's still カラオケ, the same topic established in the first half of the
sentence. So it can be rephrased as カラオケは日本が世界中に誇る文化なのである。

日本が世界中に誇る is a relative clause modifying 文化, so the whole thing means
something like "Nowadays, karaoke is not a mere machine, but a culture for
Japan to proudly display to the whole world."




The なの is just a case of the "explanatory の" which adds a slight explanatory
nuance to the sentence but doesn't directly affect the meaning much, so it's
fine to leave it out in the translation.

However, I think you're interpreting the grammar of the rest of the sentence a
little wrong. The subject (topic) of the second part of the sentence isn't
Japan - it's still カラオケ, the same topic established in the first half of the
sentence. So it can be rephrased as カラオケは日本が世界中に誇る文化なのである。

日本が世界中に誇る is a relative clause modifying 文化, so the whole thing means
something like "Nowadays, karaoke is not a mere machine, but a culture for
Japan to proudly display to the whole world."

