Something about patience being a virtue and all that jazz...
We're not 100% sure what's involved in adding languages to the app, especially when those languages require significant design changes (like Japanese, for instance). So for the moment, we're going to avoid giving out defined timelines until we can be sure about them.
Be aware that we're doing our best to get everyone's languages out as rapidly as possible. Many of us are waiting for these languages as well.
Gabe, in particular, is chomping at the bit to use this app for his own Japanese (and Japanese is one of the last releases), and we have a lot of financial incentives to release languages rapidly, as well. (Note that your subscriptions don't actually start until you're learning your target language).
So rest assured that there's lots of incentive for us to move quickly, but we also want to give our development team the time they need to ensure we are giving you only our very best.
In an effort to keep things as transparent as possible, we have both our Fluent Forever Progress Site and our *NEW* Language Content Development Schedule available, so that our supporters are as up-to-date as possible on things in the works.