Software:Comparison of speech synthesizers

Here is a non-exhaustive comparison of speech synthesis programs:

General

Name	Creator(s)	First public release date	Latest stable version	Software license	Cost
Alfanum TTS	Alfanum	2004	2018	Proprietary	?
Apple PlainTalk	Apple Inc.	1984	2018	Bundled with Mac OS X	Bundled
AT&T Natural Voices	AT&T Natural Voices	?	2008	Proprietary	$295 – $995
Polly	Amazon AWS	2016	2019	Proprietary	$4.00 per 1 million characters (free in 1st year)
Cepstral	Cepstral	2000	2013	Proprietary	$29+
CereProc	CereProc	2006	2017, February	Proprietary	£25.99+
CPqD Texto Fala	CPqD	1999	2016, March 1st	Proprietary	?
eSpeak	Jonathan Duddington	2006, February 10	2010, December 2	GPLv3+	Free
Ekho	Cameron Wong	2008, March 26	2021, April 06	GPLv2+	Free
Expressive Speech	Voxygen SAS	2011, September	?	Proprietary	Not Free
Festival Speech Synthesis System	CSTR	?	2014, December	MIT-like license	Free
FreeTTS	Paul Lamere Philip Kwok Dirk Schnelle-Walka Willie Walker ...	2001, December 14	2009, March 9	BSD	Free
LumenVox	LumenVox	2011	2019	Proprietary	?
Microsoft Speech API	Microsoft	1995	2012	Bundled with Windows	Bundled
VoiceText	ReadSpeaker (Formerly Neospeech)	2002	2017	Proprietary	?
Nuance Vocalizer	Nuance Communications, Inc.	?	2018	Proprietary	Not Free
Praat	Paul Boersma David Weenink	1991	2021, February 28	GPL	Free

Technical voice details

Platform	SSML	SAPI version	WS	PLS	CLI
Alfanum TTS	Yes	4.x/5.x	?	?	?
Apple PlainTalk	?	?	?	?	?
AT&T Natural Voices	Yes	5.1	?	?	?
Cepstral	Yes	5.x	Yes	Yes	Yes
CereProc	Yes	5.x	Yes	Yes	Yes
CPqD Texto Fala	Yes	?	Yes	?	Yes
Ekho	?	?	?	?	?
eSpeak	Yes	5.x	?	?	Yes
Expressive Speech	1.0/1.1	5.x	?	Yes	?
Festival Speech Synthesis System	?	?	?	?	Yes
FreeTTS	?	?	?	?	?
LumenVox	Yes	5.x	Yes	Yes	Yes
Microsoft Speech API	5.x only	4.x/5.x	?	?	?
Nuance Vocalizer	?	?	?	?	?
Praat	?	?	?	?	?
VoiceText	Yes	5.x	?	?	?

Technical details

Name	Online demo	Available language(s)	Available voices	Programming language	Operating system(s)
Alfanum TTS	Yes	Serbian, Croatian	8	C++	Windows
Apple PlainTalk	?	English (United States), ...	15+	?	Macintosh
AT&T Natural Voices	Yes	English (British), English (Indian), English (US), French, French (Canadian), German, Italian, Spanish (Latin American)	20	C++	Linux Windows
AWS Polly	Yes	Arabic (arb), Chinese, Mandarin (cmn-CN), Danish (da-DK), Dutch (nl-NL), English (Australian) (en-AU), English (British) (en-GB), English (Indian) (en-IN), English (US) (en-US), English (Welsh) (en-GB-WLS), French (fr-FR), French (Canadian) (fr-CA), German (de-DE), Hindi (hi-IN), Icelandic (is-IS), Italian (it-IT), Japanese (ja-JP), Korean (ko-KR), Norwegian (nb-NO), Polish (pl-PL), Portuguese (Brazilian) (pt-BR), Portuguese (European) (pt-PT), Romanian (ro-RO), Russian (ru-RU), Spanish (European) (es-ES), Spanish (Mexican) (es-MX), Spanish (US) (es-US), Swedish (sv-SE), Turkish (tr-TR), Welsh (cy-GB)	60 (male, female for most languages. For some languages child and different dialects are available)	Undisclosed by AWS	Cloud-based online software with API adoptable for all currently available operating systems
Cepstral	Yes	English (British), English (US), Italian, French (Canadian), German, Spanish (American), ...	25+	C/C++	Mac OS X Windows i386-Linux x86-64-Linux Sparc-Solaris i386-Solaris
CereProc	Yes	English (British), English (US), English (Scottish), English (Irish), French, French (Canadian), German, Austrian German, Italian, Irish, Spanish (Castilian), Spanish (Latin American), Dutch, Polish, Portuguese, Portuguese (Brazilian), Japanese, Catalan, Scottish Gaelic, Swedish, Russian, Mandarin	46	Java / C C++ / Objective C / Python / C# & .Net through SAPI	Linux Windows Mac OS X Embedded Linux Android iOS Cloud service
CPqD Texto Fala	Yes	Brazilian Portuguese, Latin American Spanish, US English	5	C, C++ and Java	Windows Linux Android iOS
Ekho	Yes	Cantonese, Mandarin (standard Chinese), Zhaoan Hakka (a dialect in Taiwan), Tibetan, Ngangien (an ancient Chinese before Yuan Dynasty) and Korean	7	C++	Linux Windows Android
eSpeak	Samples	Afrikaans, Albanian, Armenian, Cantonese, Catalan, Croatian, Czech, Danish, Dutch, English (British, US, Scottish, Westindies...), Esperanto, Estonian, Finnish, French (France, Belgium), Georgian, German, Greek, Hindi, Hungarian, Icelandic, Indonesian, Italian, Kannada, Kurdish, Latvian, Lojban, Macedonian, Malayalam, Mandarin, Norwegian, Persian, Polish, Portuguese, Romanian, Russian, Serbian, Slovak, Spanish, Swahili, Swedish, Tamil, Turkish, Vietnamese, Welsh.	Several	C++	Linux Windows Mac OS X RISC OS
Expressive Speech	?	French, French (Canadian), French (African), UK English, US English, Spanish, German, Italian, Arabic, Wolof	50	C/C++/Java/Python	Windows Linux Android
Festival Speech Synthesis System	Yes	English (UK), English (US), Spanish, Hindi, Croatian, Finnish, Polish, Welsh.	Several	C++	Linux Windows
FreeTTS	?	English...	Several	Java	Cross-platform
LumenVox	Yes	Danish, Dutch, English (Australian), English (US), English (UK), English (Welsh), English (Indian), French, French (Canadian), German, Icelandic, Italian, Polish, Portuguese, Portuguese (Brazilian), Romanian, Russian, Spanish (North American), Spanish (Latin American), Spanish (Castilian), Swedish, Turkish, Welsh, Welsh English	57	C/C++	Windows Linux
Nuance Vocalizer	Yes	US English, Australian English, Indian English, Irish English, South African English, UK English, Argentinian Spanish, Castilian Spanish, Colombian Spanish, Mexican Spanish, Arabic, Catalan, Basque, Galician, Dutch, Belgian Dutch, Portuguese, Brazilian Portuguese, Bulgarian, French, Canadian French, Cantonese (Hong Kong), Mandarin, Mandarin Taiwanese, Czech, Danish, Finnish, German, Greek, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Norwegian, Polish, Romanian, Russian, Slovak, Swedish, Thai, Turkish	70+	C/C++	Windows Linux Android
Praat	?	?	?	C	Windows Linux Macintosh FreeBSD Solaris
VoiceText	Yes	English (US), English (British), American Spanish, Canadian French, Chinese Mandarin, Japanese, Korean	13	C/C++/Java	Windows Linux

Text-to-speech engines on Android

Name	Creator(s)	Available languages (voices)	Latest version	Last updated	Google Play Store rating
Voxygen - Expressive Speech	Voxygen	6 (50)	1.6.0	2017-12	varies (4-5)
Acapela TTS Voices	Acapela Group	35 (100+)	4.0.0.6	2015-04-07	3.6 (2,111)
CereProc Text-to-Speech	CereProc	11 (26)	4.0.5	2017-03	varies
Eloquence Text-To-Speech	Nuance	10	1.2.0	2015-03-02	4.3 (129)
eSpeak	eSpeak	40+	1.46.02	2012-12-14	3.3 (1,762)
Google TTS	Google	13 (16)	?	2015-04-07	4.0 (429,325)
IVONA Text-to-Speech HQ	IVONA	13 (13)	1.6.42.524	2015-06-23	3.9 (14,413)
NeoSpeech NewsSpeak	NeoSpeech	1 (7)	1.1.0	2014-12-30	4.8 (16)
SVOX Classic Text-to-Speech	Nuance	25+ (40+)	?	2012-09-28	3.7 (15,740)
Vocalizer	Nuance	36 (80+)	1.0.5	2015-04-23	3.5 (487)