Hi,
As others suggests you can use MorphVOX from ScreamingBee: http://screamingbee.com/Product/MorphVOX.aspx

I have used it myself in this film (25 min): https://youtu.be/B4wR1aijHB4 - where ALL voices are recorded by me through MorphVOX. Language is danish (feat. english subtitles) but it should give you an idea of whats possible. This film is featuring 10 different characters and 3 speakers (you'll meet/hear 'em all about halfway through the film), which all of them is me speaking. Nobody else involved, it's all only me!

It takes some time to adjust the settings you're looking for to get the voices you want. But it's far better than just twisting the pitch in Audacity etc. I myself tried a lot of things out for my film above, but no doubt that MorphVOX did the best job whatsoever, so that my absolutely best recommandations to your question.

Kind regards,
Brian O'Brixtor
http://obrixtor.com/

Ahh yes, computer generated voices....ok but nothing like the real deal.
There are many small and large companies that do voice overs. Some are cheap. Search for them and see what deal you can get.  Real voices are best.
Personally, I think we can ask on the forum for someone to do a small voice clip and pay them for it......????? Think of it, most languages and dialects too..... extra cash is nice. Make a deal.......lol Paypal makes it easy too.
friends and family can help too.....???? or a local school with 3d animation classes or theatre. They too can always use some xtra cash.


MSI GE66 Raider, Intel 10th Gen, I7, SC Turbo to 5.3 GHZ, 240HZ, 64GB 3300 Ram,  2x 1TB M2 SSD Drives, NVIDIA GPU RTX 2070/8GB, 55" Sony 4K Monitor  External data drives total 7 TB. and an AUDIO Studio Recording system.

There are many software to change your voice out there. But to me, a friend of mine used AV Voice Changer Software Diamond and the result is amazing.
https://www.youtube.com/watch?v=-0C5RrRYVfg
This is the video that he made and it's awesome with all the voices. The software is really good when recording and editing, in my opinion. You can give it a try.