Installing the Festival Speech Synthesis System with Mavericks
Here is an email reply I got from Rob Clark (one of the creators of Festival):


  Use the speech_tools and Festival packages, then
  unpack and run make in each directory.
  
  You will also need dictionary and voice packages from the standard download site.
  The festvox and festlex packages should be unpacked in the directory
  above festival (i.e. where you unpacked the festival package itself)
  
  Regards. Rob Clark.


Since Rob responded to my email with in hours, feel free to contact him for more information if needed robert@cstr.ed.ac.uk

As mentioned in the comments, unpack the festvox and festlex packages with the command line, and not the Mac's default unpacking software.