Dubstepforum.com

i made a thread about this a while back. didnt know the name for it then. guess its called changing the pitch of formant frequencies in an audio. i found a plugin that could do this kinda but tbh it didnt quite nail it and was a trial version and i aint paying for wack ass plugins so preferably free plugins that can do this to vocals. alternatively if there's a way to go round it with ableton's native plugins lemme know

You can do it in Ableton by changing the clip warping to Complex Pro and adjusting the Formant parameter. I don't think you can automate it, though, so you'd have to do it by hand while you record it to audio.

Edit: Could also try using Vocoder with the carrier set to Modulator and then modulating the Formant knob. This might not get you where you want to go, though.