I studied Japanese as an elective at uni a few years back for 2 terms. Despite it using Chinese characters (kanji), the language itself is not that hard.
As the Japanese people were originally a nomadic people who skirted round the borders of China and on the Silk Route etc, the language is actually a blending of a range of languages, and the language became a more 'pigeon' language to compensate - e.g. if lots of people from different countries come together and try and communicate, the result is probably slightly more simplified, for things like grammar, etc.
So the grammar is not too hard, and as long as you learn from someone who knows that when you say "desu" it's pronounced more like "dess" - with a very soft "u".
Japanese is made up from contiguous syllables, each with the same length in pronounciation - there are 46 syllables in total, e.g. "ku", "ki", "ka", "ke", "ko", "du", "so", etc, and words are made out of these syllables.
In terms of writing Japanese, they have 2 phonetic alphabets (hirigana and katakana), in which each character corresponds to one of the 46 syllables. They also have kanji, which is the Chinese picture characters (approx 10,000), and which I believe Japanese monks 'borrowed' from Chinese back in the early years AD.
I highly recommend learning, and compared with languages such as English, German, French, etc it's not too hard - although, as I say, it's best to learn from a Japanese speaker to get the proper pronounciations.
Hope this helps.
