In the past, we've discussed the possibility of a localized interface for Japanese.SE:
- Is JLU an English-centric site? & Is it possible to create a localized JLU for Japanese?
- Creating as much Japanese interface as possible to be more inclusive of native Japanese speakers
- Localization: The state of the nation? (Meta.SE)
But things have changed since then. Japanese Stack Overflow now exists, and its interface has been translated into Japanese. Why not allow the Japanese interface here, too, as an official option?
This would help us encourage participation from native Japanese speakers.