I've known an english variant of the "flick" keyboard (MessageEase) since my first smartphone.
I find the flick/tap-and-drag gestures to be vastly more comfortable and natural than trying to use my thumbs to peck at a QWERTY soft keyboard and relying on predictive algorithms to make up the speed loss.
An additional benefit is that this approach provides more room for additional symbols and layers that are more of a bother to reach from standard soft-keyboards. For example, I can have a full set of programming symbols with Ctrl/Esc modifiers available without explicitly mode-switching the keyboard, it's extremely helpful when I'm ssh-ing from my phone.
For reference, with a physical QWERTY keyboard I average around 95 wpm, with messagease on my phone I run around 60 (without autocorrect/suggestions).
I've used MessageEase for years now on Android and it was really worth the time investment. I only switch back to Gboard occasionally to get at its far superior emoji input system, but I don't use a lot of emoji in most of my text entry so that's not a massive deal. I can type accurately without having to wrestle with autocorrect all the time, and that'll do for me! And although the letter frequency distribution isn't right, I can happily use it to enter German and Lojban and Welsh on the occasions when I want to use those on my phone.
I haven't gone too far myself, but I'm pretty sure it's possible to customize the symbol layout to better suit a particular language or user preference.
IIRC you can swap out (or add) any of the side/minor triggers, but I don't recall if it's possible to change the big nine major keys.
It is great though, I abhor word prediction when I'm trying to write (the smarter the predictions, the more viscerally disturbing I find it), and ME has been the only way I can keep up a comfortable pace.
I find the flick/tap-and-drag gestures to be vastly more comfortable and natural than trying to use my thumbs to peck at a QWERTY soft keyboard and relying on predictive algorithms to make up the speed loss.
An additional benefit is that this approach provides more room for additional symbols and layers that are more of a bother to reach from standard soft-keyboards. For example, I can have a full set of programming symbols with Ctrl/Esc modifiers available without explicitly mode-switching the keyboard, it's extremely helpful when I'm ssh-ing from my phone.
For reference, with a physical QWERTY keyboard I average around 95 wpm, with messagease on my phone I run around 60 (without autocorrect/suggestions).