I think we will not end up with a truly bilingual interface to our site, but since we're hoping to involve not only learners, but also native speakers of Japanese, we have tried to make the interface at least a bit more accessible for native speakers.
I just noticed again that we can change the introduction to our tour, which currently reads
Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. It's built and run by you as part of the Stack Exchange network of Q&A sites. With your help, we're working together to build a library of detailed answers to every question about the Japanese language.
and I think it might be nice to include a Japanese translation of this paragraph to make the site feel more bilingual for people new to the site.
The rest of the tour will be in English, but if at least the opening paragraph has a Japanese version, I think it would be nice. (There doesn't seem to be a character limit, although if it is too long, it will be cut off. Currently twice the length of this paragraph seems to fit though.)
What do you think?