Speech

Elan Speech
Offers Elan Sayso natural sounding text-to-speech for Mac OS X. Available in 12 languages.
http://www.elanspeech.com/

IBM ViaVoice (US English)
Continuous speech recognition for your Mac.
http://www.nuance.com/viavoice/osx/

MacSpeech
Home of iListen, a Speech Dictation/Command software for Mac OS. Includes news releases, online store, and tech support.
http://www.macspeech.com/

Speechissimo
Converts any written text into speech using Elan Sayso text-to-speech technology. Speechissimo can speak multiple common languages. For Mac OS X.
http://www.speechissimo.com/