[sillysaurusx]

They’re saying that underrepresented voices will have trouble being modeled. That matches my experience with this project: for example, I had a very tough time cloning female voices compared to nerdy-sounding / deep male voices.

[zamubafoo]

It's more that the sounds produced during the recordings didn't cover the entire spectrum of possible sounds, so the model had to estimate their sound. All you really need is a paragraph which you can have the person read to get sufficient coverage or just enough recordings that it's not an issue anymore.