check the vocal harmony chapter in Genos user manual.
Page 76.
If you selected the Vocoder or Vocoder-Mono Type:
5-1 As necessary, change the “Keyboard” setting to “Off,” “Upper,” or “Lower.”
When “Upper” or “Lower” is selected, playing the right-hand or left-hand
section of the keyboard will control the Vocoder effect. When “Off” is
selected, playing the keyboard will not control the Vocoder effect.
5-2 Play melodies on the keyboard or play back a Song, and sing into the microphone.
You’ll notice that you don’t actually have to sing pitched notes. The
Vocoder effect takes the words you say and applies them to the pitch of the
instrument sounds.