Another F/OSS personal assistant. Skill-based. Speech recognition and synthesis. Uses node.js and Python.
Jarvis is an ultra-light and multilingual voice assistant. Designed for home automation, it can run on energy efficient systems (eg Raspberry Pi). Very easy to use, it leaves you the choice of recognition engine and speech synthesis and installs them for you. It is extremely customizable, including via the addition of plugins. French and English.
The eSpeak NG (Next Generation) Text-to-Speech program is an open source speech synthesizer that supports 102 languages and accents, based on the eSpeak engine created by Jonathan Duddington. It supports spectral and Klatt formant synthesis, and the ability to use MBROLA voices.
Online service that does text-to-speech as a service. Free at the low end, cheap at the high end. If you can send it text (even an RSS feed!) it will read and turn it into recorded audio with a synthesizer. Supports 26 languages.
audio computers development free freeware opensource oss programming server software sound technology text tools speech text-to-speech tts speechsynthesis
A Python module which implements interfaces to the native text-to-speech API for whatever platform you're running it on, be it Windows, MacOSX, or Espeak on Linux.
F/OSS voice control system. Runs on a raspi. Extensible. Uses speech synthesis to respond.