Keyboards

Hey I was wondering if anyone knows how I can change the default keyboard.

I know this is a little bit odd. But I want to figure out how to add a Morse code keyboard with ideally a different button selection to kick it off.

I know the basics of Morse (it is pretty easy with Google's training website).

So without a keyboard I would like to be able to change the back 4 grip buttons to:

Top left short dash, top right long dash, bottom left control (so I can hopefully hold it or click it to use multiple keys at once), and bottom right keyboard appear and disappear.

Anyone want to help me make my goofy dream a reality?

Using the keypad on screen means having to move your hands off the controls, using the keyboard with the touch pads is kinda challenging to do quickly, and the buttons to bring up the keyboard are slightly annoying to use.