I pasted her post for convenience:

"Yes this is all on Tyros 4.You just need to set it up.You do have to record your song though and you need to record the right hand part onto the track you have picked for the vocoda.Once recorded you need to set the volume balance down to nil on this track.Asign the slider to VH Balance.Set the pitch correct to Hard.Select Vocoda MONO.Press funtion and song setting Set to Karao-Key.Set vocal balance to around R37.It is advisable when you record your melody track which needs to be played using single notes to slow this down to half speed and use the metronome if needed holding the notes for the full duration.You can then set it back to the right speed.You then follow with what you saw on the Demo pressing any note on the upper part of the keyboard in time with your vocal
Have Fun "