cgo interface to WebRTC Voice Activity Dectection
a small speech synthesis library for ruby using CMU Flite(http://cmuflite.org)
CMU PocketSphinx for Golang, a lightweight speech recognition engine.
Open-Source Large Vocabulary Continuous Speech Recognition Engine
graph-based audio engine
D-STAR voice-announcement system
Echo Canceller, part of Voice Engine project
The voice project of Embedded System use STM32
DIY Voice HAT like AIY Projects Kit HAT
Voodoo Voice lets you control iTunes (Windows) with spoken commands such as "begin play", "next song", and "switch to <name of song in play list>". It is speaker independent and surprisingly accurate. See the official web site below for more information.