But looks suspiciously like retrocomputing to me!
Interesting, but not a new idea… For a more ‘retro’ one, then …
The Microwriter was a stand-alone device originating in the late 1970’s…
There was also a spin-off called the Quinkey which you could use with a BBC Micro and I used one for a short while, however after not using it for a week or 2, I more or less forgot how to use it, so never bothered after that…
I remember reading about some later chord keyboard in some computing mag in … mid-1980s?
Fun fact: Chorded keyboards (at least the Engelbart ones) are just manual input devices for Baudot code. Be your own ticker tape!
Edit: with 12 keys, we could go fully EBCDIC.
(Mind that there are never more than three punch holes or keys to be pressed at once in classic Holerith code.)
That was likely the Microwriter AgendA, one of the first PDAs. It had a conventional keyboard as well as the Microwriter chording keys.
Vik Olliver (one of the hardware designers at Amstrad, and later a 3d printing pioneer) worked on Microwriters and Quinkeys, and has released an Arduino-based 3d-printed Microwriter-alike: VikOlliver/Microwriter: A reboot of the 80’s Microwriter accessible chord keyboard done using an Arduino. I built one, and it worked quite well, but the choice of switches needs a little work.
Other chording devices that see other than niche usage:
Stenography, used in court reporting. This is an amazingly locked-down toolchain for such important legal work, but Open Steno is working to open it up.
Braillers, for people experiencing vision loss who know Braille. Like all assistive devices, Braillers tend to be incredibly expensive. Braille printing is still almost exclusively mechanical (loud!) impact printing that uses expensive thick paper.
As I (currently — until the end of the month) work for an assistive technology charity, I couldn’t pass up the chance to mentioned the inverse of chording keyboards: single-key Morse keyboards! These help people with very limited movement to access computers. For instance, one person I know of wrote their entire PhD thesis using a bite switch and morse controller. An example of a very advanced one of these input devices is the Feather All-in-One Switch from Makers Making Change, the group I work for.