I am a native Californian who is fluent in Japanese. I became fluent in Japanese while I was a Mormon missionary in Japan for two years (1986-1988). I received two months of intensive language training before I went to live in Japan as a missionary.
As a missionary I spoke Japanese for approximately 10 hours per day with native Japanese. While the language training process is not as formal as college classroom environment, I believe it is actually much more effective to learn a language...
I am a native Californian who is fluent in Japanese. I became fluent in Japanese while I was a Mormon missionary in Japan for two years (1986-1988). I received two months of intensive language training before I went to live in Japan as a missionary.
As a missionary I spoke Japanese for approximately 10 hours per day with native Japanese. While the language training process is not as formal as college classroom environment, I believe it is actually much more effective to learn a language by talking with native speakers in their native land. I studied Japanese out of Japanese manuals every day for ~1 hour for the two years that I was in Japan. By the end of my period of living in Japan, I was completely fluent in Japanese. I also lived in the Kansai region (Osaka, Kobe, Kyoto) and was able to pick up "Osaka-ben" which is the regional dialect spoken by native speakers of Kansai.
Since I lived in Japan almost 30 years ago I have travelled to Japan about 10 times over the years. I also lived in Japan during 2000 (working for a Japanese cell phone company). I worked in a Japanese office setting as a manager of 6 Japanese employees.
Again, while I do not have formal certification as a Japanese language instructor, every Japanese person I have met in America has remarked how natural my Japanese sounds. Since I have lived in Japan and talked with hundred of Japanese I know what it is like to be a foreigner in Japan and how to use Japanese successfully in a variety of social settings. If you are going to Japan, I think that my conversational Japanese approach will be much more successful than just learning Japanese out of a book.