I see mention of T9 in "On phones that used the 9-key numeric layout, T9 predictive text was used. Other phones used the full-hand layout with the familiar QWERTY layout, with other proprietary predictive methods." I'm unable to verify this app has T9 as an input method. Is there a custom layout for this?

T9 was pretty sweet as you could type without needing to look at the device.

Maybe this layout?

https://github.com/dessalines/thumb-key/issues/263

https://docs.google.com/spreadsheets/d/1i6scYO3PHnyvA_JwB09W...