I’m sure there are lots of no-Japanese otakus know Japanese
I started to learn Japanese 4-5 years ago because of anime.I wanted to be able to watch raw anime so I don’t have to wait for subs, and also be able focus more on the actual anime (those nice ‘eyes’ for example XD ), not the words at the bottom or the top of the screen.
Love for anime was really powerful, it keeps me willing to learn Japanese until now.
However my Japanese knowledge isn’t growing much, mostly because I don’t have chance to use it (except from watching anime and read manga)
Now I can understand most of the casually conversations in anime. I watch most of the Slice of life anime without subtitle. But for the complicated one, such as Code Geass, I still keep the sub so I can understand every detail (assuming the subs are perfect)
For the Japanese learner otakus, have you ever hear about Japanesepod101.com ?