Aufgegeben von in Japan Forum
I'd say it depends a lot on the person, his/her dedication and exposure to the language.
Japanese grammar is soooo much easier than German's. (studying German now) So within a year I think you could start making correct everyday life sentences.
The two alphabets are easy, the kanji are hard. Japanese study them all life long. You'd need years of kanji studying to be able to read a Japanese newspaper.
My wife is Japanese, if you are interested in some basic courses, she could help you. Just let me know.