These are the programs implementing the actual speech recognition:
See also https://en.wikipedia.org/wiki/List_of_speech_recognition_software
There were several packages for driving Emacs through voice input, but none currently maintained.
VoiceCode is an Emacs interface to Dragon NaturallySpeaking (uses Natlink, updated Sept 2, 2019). https://sourceforge.net/projects/voicecode/ The last update to the SVN repository was in 2013.
A voice-controlled keyboard for GNU/Linux built on sphinx. http://sourceforge.net/projects/voicekey/ (unmaintained since August 2013, see https://sourceforge.net/p/voicekey/voicekey/ci/329cc8daac480349a3308121d9e8d35a01725ed4/)
Emacs interface to Dragon NaturallySpeaking. http://emacs-vr-mode.sourceforge.net/
The last release announcement (as of Oct 2013) was in 2007… http://sourceforge.net/mailarchive/forum.php?forum_name=emacs-vr-mode-announce
EmacsListen is an implemention of ShortTalk. It is based on vr-mode.
http://shorttalk-emacs.sourceforge.net/
EmacsListen is unmaintained. The latest commit in its CVS Repository was in 2004. – XueFuqiao