Comment by pasta

As I remember this was done on an Apple computer.

In the command line you could do this with they 'say' command.

The parameter -v is used for the voice. And I think "Fitter Happier" is 'Fred'.

  say -v Fred "fitter.happier.more productive"

Edit: other sources say it was 'Bruce'. But I don't have an Apple, so I can't check.