eSpeak is a compact open source software speech synthesizer for English and other languages, for Macintosh Linux and Windows. The source can be found at: http://espeak.sourceforge.net
This Macintosh package installer will install eSpeak on your computer as well as directing you to the eSpeak documentation. At this time eSpeak is not intergrated with the Speech Manager of the MacOS.
mbrola adds voices and langauges to eSpeak. One interesting feature is English language voices which speak in accents. For example you can have English spoken in a French accent. The installer is large at over 200 megabytes.
eSpeak Utility is an experimental program for speaking text with eSpeak voices it is included in the installer and can be found in your applications directory. You will need to have eSpeak installed to use it. This installer will install both eSpeak and the utillity program.