There were a _lot_ of programs in this space, one of the more interesting was AlphaTap! by Network Improv:

http://networkimprov.net/alphatap/light.html

c.f., the research project:

https://dasher.zone/docs/getting-started/how-to/

For my part, I just write text out using a Wacom stylus on my Note 10+

TY for the flashback: I'd learned Dasher! Jesus-phone had washed that away.

I kind of miss my Compaq iPaq, Danger Hiptop, Handspring Visor ... OK, one of those is not like the others, but it was ideal UX for the time.

>Type by zooming infinitely into a prediction model

Holy crap that's a trippy GIF