Actually, Palm handled it nicely back in the PalmOS era (both with the hardware foldable keyboards and the on-screen one that can be used instead of Graffiti) :
The keyboard layout is US,
but nearly any additional symbol is available by using "Alt"+key (and those Alt combo follow the same layout as the on-screen display of alternative chars).


By the way, I hope that this upcoming device will easily work with rotation in any orientation. (Or at least can easily be patched to)
I would love using it in "reverse portrait" (with the connectors on the top, like current jolla device).
Useful to plug in earphone (or a powerbank) when in the pocket.

Also doesn't require a dock when charging on a desk while propped up (e.g.: to use with a full sized bt keyboard)