Morse is readily adaptable to whatever you can sense: I've experienced it with sound, light, and vibration. Taste, heat, and smell might not work so well.

For input, you need to be able to reliably close and open a switch. This may be difficult for people with tremors, but many accessibility systems are built around single bit inputs, so it's a start. If you can manage another input method, it can be translated to Morse as well.

Internationalization is harder, it's not a good fit for non-alphabetic languages.