Text To Speech providers

Supported languages matrix
iSpeech : iSpeech cloud API
Polly : Amazon TTS cloud
Microsoft Speech API : Microsoft voices
NeoSpeech : Free and Commercial
Nuance : Commercial, MRCP only
Voxygen Cloud : Caching not allowed, no more commercial offer
Flite : Free and OpenSource
uniMRCP : uniMRCP (universal MRCP connector) OpenSource GPL

Text To Speech providers LEGACY