hi am follow this project for a some time and as a Linux user with dyslexia. The first question that i have is there a libraries version for building other software. Second question is there a offline mode.
The reason of the first question is that the current TTS packets on linux (Festival, espeak) have no easy way to interface to other software with out execute a shell command. Another problem with the exec method is the length of the text, this can be the problem with the software that i use or the data is send via the command line.
The idea behind the offline mode is for offloading wikimedia servers and using for Third party application on PC/raspberry pi for example Calibre or a screen reader.
Last this is not in my two question but a note on the current state of TTS under linux is that the current Free/open Source voices are bad qualety (espeak) or the software is open source but the TTS voices are close source or a restricted license. And a good guideline is MS SAM (sapi 4 and sapi 5) for the minimum quality for a TTS voice that use in an production environment.