There are other ways, for example Ximik_Boda designed T2, a “pro” input method for T9 keyboards. Pressing a key, such as 8/TUV, brings up a popup that shows the mapping of characters to the second key, here 1=t, 2=u, 3=v, 0=8. Every lowercase letter, number and symbol can be typed with exactly 2 key presses, and there is no annoying wait when typing words like “nonmonogamous” with 7 waits for the 6/MNO key multi-click to time out.
Unfortunately, the order is important, for example 62 is n and 26 is %. Unordered pairs (9 keys and 2 legs) only allow for 36 combinations, which is not enough. 7² for 49 combinations plus two special keys, a modifier and a mode switch (lowercase/uppercase/navigation) seems to be optimal.
There are other ways, for example Ximik_Boda designed T2, a “pro” input method for T9 keyboards. Pressing a key, such as 8/TUV, brings up a popup that shows the mapping of characters to the second key, here 1=
t, 2=u, 3=v, 0=8. Every lowercase letter, number and symbol can be typed with exactly 2 key presses, and there is no annoying wait when typing words like “nonmonogamous” with 7 waits for the 6/MNO key multi-click to time out.Unfortunately, the order is important, for example 62 is
nand 26 is%. Unordered pairs (9 keys and 2 legs) only allow for 36 combinations, which is not enough. 7² for 49 combinations plus two special keys, a modifier and a mode switch (lowercase/uppercase/navigation) seems to be optimal.