Go in Orca Preferences --> Speech tab and change the "Speech System" to 'GNOME Speech Services' After that, you can change the "Speech synthesizer" to Festival.
But some times you do not get 'GNOME Speech Services' option in "Speech System" for that install
libgnome-speech7 :
$ sudo apt-get install libgnome-speech7
Note: You may get following error
E: crossplatformui: subprocess installed post-installation script returned error exit status 1
Solution: Ignore the error. Festival will work
More about it in this thread:
https://answers.launchpad.net/ubuntu/+question/113136
It means only that "crossplatformui" is not managed by Ubuntu distro team, and that you have to check by yourself if current version is compatible with Lucid.
The risk applies only to "crossplatformui".
You have also to check in Synaptic is deposit for this package is always active.
Note: "crossplatformui" is a Reliance net connect usb driver.
