I was working on a keyboard a while back; I should dust off that code and see what can be done with it. I've been testing OKboard on Jolla and on OPX (third-party port without xt9). On the OPX it's pretty terrible; not just for the lack of predictions in normal typing, but because it tries to use xt9's predictions bar for its own predictions when swiping, meaning that without xt9 there are no predictions whatsoever. And no ability to correct a word; you have to swipe and hope you nailed it.