Keyboard and voice navigation, analog "voystick" vocal joystick formant/pitch tracking:

Voystick:

https://github.com/elisaoh/mypystick

Vocal Joystick:

https://www.youtube.com/watch?v=PXmccs4GIqI

Vocal Joystick Home Page:

https://web.archive.org/web/20100626050314/http://ssli.ee.wa...

University of Washington: Department of Linguistic: The Vocal Joystick

https://linguistics.washington.edu/research/projects-and-gra...

Guitarists have been using their picking hand or pedal controls since the beginning of the electric guitar without much fuss or concern.

I also thought pie menus died off because everyone decided they were too limited, hard to understand, and overall annoying regardless of the input method.