mbrola is a non-free phonemes-to-audio program.
Step 1: Installation
A package is available in AUR.
Step 2: Add voices
Packages named mbrola-voices-xxx are available in AUR.
Step 3: Testing
Once you have installed the wanted voice(s) go to the directory of the installed language:
$ cd /usr/share/voices/us1/
then list the test files:
$ ls TEST/
If there are no test files for this language skip this test and go to step 3 or try with an other language. Else choose a test file (files with .pho extension) and try:
$ mbrola ./us1 ./TEST/mbrola.pho ~/test.wav; aplay ~/test.wav; rm ~/test.wav
If you here a voice it works, if not, check that you did everything good and if it still don't work go ask for help on forums.
Note that we didn't give a text file to mbrola but a phoneme file so we don't have a text-to-speech system yet so lets see the next step.
Step 4: Install a text-to-phonemes program
To obtain a full TTS system we need a text-to-phonemes program compatible with mbrola: List of TTS programs compatible with mbrola.
LLiaPhon is a TTS program which uses mbrola.
See the detailed article: lliaphon