[Drako]

They're very different, historically, Japanese used Chinese as their main language. But after a feud( the rape of Nanking) they decided to use a tribal Japanese language, which later evolved to the main language of the island.

Still, they don't have all the vocabulary, hence borrowing words from Chinese.

I read that for an English speaking person to speak Japanese fluently, it'd take 22,000 hours of studying.

I guess, because you also have to learn kanji.

Similarly,
The word for I/me

Mandarin 我 wo
Cantonese 我 ngǒ
Japanese kanji 私 (I don't know how to pronounce, but in Chinese it's si )
Hak-kâ-ngî 雁 ngan/ngaan


That shows that they are quite different.
Altough all came from Chinese.

If my memory serves me well, I believe 私 is pronounced, Matashi (Mahtahshee) which is obviously very different from Si.