Is there voice-changer software for Mac?

[Roses]

Hi all:

I am looking for some sort of voice-changer software for Mac OS X ... is there such a thing?

For Windows, for example, I am finding in my Google search, something called "AV Voice Changer Software." But it seems to only be available for Windows PCs and not Mac.

I need this sort of thing for my Mac.

What I would like to do is to take recorded speech of someone's natural voice, (using a digital file like an .aiff file or .WAV file of someone's speech or whatever) and then transform that recorded natural voice into a computer-generated voice like the "Bruce" or "Victoria" voices found in the Mac program.

It's part of an idea I have for solving a long-standing transcription problem ... I don't know if it will work, (in fact, it's a very much a long shot) but I'd like to try it! But, first, I need some sort of voiced-changer software that is compatible with a Mac.

Any suggestions would be welcome!