Nuendo screenshot: the plug-in played using automation tracks

Changes in vibrato: the waveform

Spectrogram of vibrato

Audio examples
Vowels: /{/ /3/
/A/ /E/
/i/ /I/
/O/ /U/
/u/ /V/
Interpolation, show
the linear interpolation. The interpolation time is short.
Vibrato, this file
shows the vibrato depth range. It's quite annoying to hear after a while.
Download here the Phoneme plug-in (.zip file).
Unzip it and you will get a .dll file. You need to put it in the vstplugins
folder of Nuendo or another host application that uses VST plugins and possibly
uses automation tracks.