I tried using the Twiddler[1] in college and found it oppressively painful to make that clenching motion, but I will admit it was super cool to be able to walk down the sidewalk and still type. The college of computing was exploring using them in their wearable computer setups, but I don't know what level of adoption they had

1: https://twiddler.tekgear.com/

Wow, I never would have guessed they still made this. Isn’t this one of the oldest ones? Looks like it has been updated.

I eyeballed the frogpad, and kept eyeballing it until they went out of business. Should have just bought one.

I suspect the oldest one is the Microwriter: https://en.wikipedia.org/wiki/Microwriter

(1978, vs. 1992.)

A form is still on sale as the CyKey: https://sites.google.com/site/cykeybellaire/

I have one. I found it almost unusable myself, because the instructions and the alphabet are intended for right-handed use. I am left-handed so for me the mnemonics make no sense, and the instruction manual devotes just a single paragraph to sinistrals, saying (summarised) "just mirror everything".

Impressive design, nice hardware, but for me, too RH-centric. Like almost all modern cameras, for example, which are virtually impossible for southpaws to hold or to use.

I've been looking into chorded keyboards a bit because of a minor temporary injury. Not really serious because the injury will be over quicker than it will take me to learn a new system, but it got me thinking:

A (as far as I know) universal chording system for both reading and typing has existed for a long time now: Braille. I think if I'd really need to learn a chorded keyboard system, I'd go for that. Maybe with some alterations to enable a one-handed setup, perhaps with foot pedals.

Does anyone have experience with that versus different chorded keyboards?

You might check out left/right Dvorak. Not chorded but gets you fewer hand movements typing one handed.

There's a hate symbol on that site.

There's also Artsey.io