tpgames3546-san,
you're very right; the root and language family for Japanese language is still very controversial.
The fact about Finnish is fairly known, and also Hungarian, if I remember correctly.
Those two are said to be related to and belong to widely-classified "Uralic languages". Japanese is
sometimes included into it (as "Uralic Altaic languages"), but the official classification recently
shows different position (in many academic and any definitions).
There are also a language family calling "Japanese language" which of course has standard Japanese
and kind of "dialects" of it (i.g. ryuukyuu go). I didn't know about this classification, but it could be a
recent new classification because they couldn't find an appropriate answer
Grammar of Japanese language is very unique and very different from any other language (= the reason why
antient European, maybe it was Portuguese...?, called Japanese language as "lanugage/tongue of devil).
There are some postings from JapanesePod listeners that learning and/or knowing Arabic is beneficial.
I don't know about it in linguistical level, but in a way, I understand why they say or think so.
When sentences are very simple, Japanese sentence like "watashi wa gakusei desu", this "A wa B desu" is versatile,
right? Such fact is close to Arabic's case. However, syntax for those two languages are not same, as far as I know.
Because Japanese language is very unique, I believe knowing many other languages is beneficial. When we know only
one language to compare, it's more difficult to analyse a new language in terms of "how this language works" issue.
If you know different languages ("different" in terms of grammar, especially), you can understand another language
more based on functions, not comparing or translating to other languages you already know.
When you come accross some typical expressions in a new language, the first thing you will feel is "I see; that's how
this language function", rather than "what's the literal translation in English?"
Natsuko(奈津子),
Team JapanesePod101.com