This page is pretty out of date, but was one of the most comprehensive listings I've seen. This is from a company called Occidental Communications:International Directory
Acapela Group
33, Boulevard Dolez, 7000 Mons, Belgium
Phone +32 6537 4275 Fax +32 6537 4276 Internet http://www.acapela-group.com E-mail webmaster [at] acapela-group.com
The Acapela Group develops TTS software for telephony circuit cards (Acapela High Quality and Acapela High Density) which it sells for use in IVR systems, for embedded applications (Pocket Babil), for telecom and multimedia applications (Babil Version 2.5 and Infovox) and for automotive, mobile terminal applications
Products Acapela High Quality and Acapela High Density Languages generated Acapela High Quality: Arabic, British English, American English, Dutch, Flemish, French, German, Italian, Norwegian, Polish, Spanish and Swedish
Acapela High Density: Czech, Danish, Finnish, Icelandic, Portuguese, Brazilian Portuguese, Russian, Turkish and South American SpanishAvailability Worldwide, via the Internet Product Babil Version 2.5, Pocket Babil Languages generated Dutch, French, Czech, British English, American English, German, Italian, European Portugese, Brazilian Portugese, Spanish, Turkish Availability Belgium, France, Germany, Israel, The Netherlands, UK, USA Product Infovox 210, 230, 310, 330, Infovox Enterprise Languages generated Dutch, French, Danish, British English, American English, Finnish, German, Icelandic, Italian, Norwegian, Spanish, Swedish Availability Belgium, Austria, Denmark, Finland, France, Germany, Iceland, Italy, The Netherlands, Norway, Spain, Sweden, Switzerland, UK, USA Product Speech Cube (enterprise and telco telephony), Networks Cube (large scale telco services), Pocket Speech (PDA), Speech engine & Digalo (PC, multimedia applications, entertainment, talking characters, productivity software) Languages generated French, Arabic, Dutch, American English, British English, German, Italian, Polish, Brazilian Portuguese, Russian, Castillian Spanish and Latin American Spanish Availability East and West Europe, Latin america, North America, India The Acapela Group also develops speech recognition and voice authentication software.
Aculab
Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT UK
Phone +44 1908 273800 Fax +44 1908 273801 Internet http://www.aculab.com E-mail info [at] aculab.com
Aculab develops TTS software for telephony circuit cards which it sells for use in IVR systems
Product Aculab Text-to-Speech V2.0 Languages generated British English, American English, French, German, Latin American Spanish. Dutch, Italian and Brazilian Portuguese in development Availability UK, Australia, Germany and the USA Aculab also develops speech recognition software.
Alcatel-Lucent
600 Mountain Ave., Murray Hill, NJ 07974 USA
Phone +1 908 582 3000 Fax +1 908 582 4630 Internet http://www.alcatel-lucent.com E-mail speech [at] alcatel-lucent.com
Alcatel-Lucent develops TTS software for implementation within IVR systems.
Products LTTS R3.2 and Articulator Languages generated LTTS R3.2: British English
Articulator: American English, Canadian French, European French, German, Italian, Mandarin, Mexican Spanish, Castilian SpanishAvailability Worldwide
Altech (Applied Language Technologies)
Renamed Speechworks, subsequently acquired by Scansoft which subsequently acquired Nuance and renamed itself Nuance Communications.
Anhui USTC iFLYTEK Co. Ltd.
Huan Shan lu 373, Hefei, an hui 230026 China
Phone +86 551 533 1800 Fax +86 551 533 1801 Internet http://www.iflytek.com E-mail bingzhang [at] iflytek.com
Anhui develops TTS software for embedded applications.
Product InterSound Languages supported Cantonese, Chinese English and Mandarin Availability China Anhui also develops speech recognition software.
Appen
Appen no longer develops text-to-speech technology and instead develops speech dictionaries for TTS software.
Applied Technologies on Language and Speech (ATLAS)
ATLAS renamed itself VERBIO TECHNOLOGIES S.L.
VERBIO TECHNOLOGIES S.L.
C/ Sabino de Arana 36, 2o, 1a., 08029 Barcelona Spain
Phone +34 934 097 120 Fax +34 934 097 130 Internet http://www.verbio.com E-mail info [at] verbio.com
VERBIO TECHNOLOGIES develops TTS software for telephony circuit cards which it sells for use in IVR systems
Product Verbio TTS Languages generated Basque, Catalan, Gallician, American English, French, Portuguese, Spanish and Mexican Spanish Availability Spain, Argentina, Chile, Colombia, Mexico, and the USA VERBIO TECHNOLOGIES also develops speech recognition software.
Aristotle University of Thessaloniki
Signal Processing and Biomedical Engineering Laboratory, Telecommunications Division, Electrical & Computer Engineering Dept
GR 541 24 Thessaloniki, Greece
Phone +30 Fax +30 Internet http://esopos.ee.auth.gr E-mail sergiadi [at] eng.auth.gr
The Signal Processing and Biomedical Engineering Laboratory develops TTS software for applications compatible with Microsoft SAPI
Product Esopos TTS Languages generated Greek and English Availability Greece
ATIP
Daimlerstraße 32, D-60314 Frankfurt am Main, Germany
Phone +49 69 710 4070 Fax +49 69 710 407 124 Internet http://www.atip.de E-mail info [at] atip.de
ATIP develops TTS software.
Product Proser Languages generated German Availability Germany ATIP also develops speech recognition and voice authentication software.
Aurix (formerly named 20/20 Speech Ltd.)
Aurix no longer develops text-to-speech software.
BaBel Technologies
BaBel Technologies has been acquired by the Acapela Group.
Bitlips Oy
Hietalahdenranta 15 C, FI-00180 Helsinki, Finland
Phone +358 40 7077723 Fax +358 Internet http://www.bitlips.fi E-mail info [at] bitlips.fi
Bitlips develops TTS software.
Product Diphone Languages generated Finnish and Finland Swedish Availability Finland
Bliss Intelligent Technologies
61 Patel Nagar, Hawa Sarak, Civil Lines, Jaipur 302006, Rajasthan, India
Phone +91 141 5545475 Fax +91 Internet http://www.blissit.org E-mail shakti [at] blissit.org
Bliss Intelligent Technologies develops TTS software.
Product Zubaan 1.0 TTS Languages generated Hindi Availability India Bliss also develops VoiceXML software.
Bhrigus, Inc.
116 Village Blvd., Suite 200, Princeton, NJ 08540 USA
Phone +1 732 398 1300 Fax +1 732 398 9080 Internet http://www.bhrigus.com E-mail info [at] bhrigus.com
Bhrigus develops TTS software.
Product Telugu TTS Languages generated Telugu Availability USA
Budapest University of Technology and Economics (BUTE)
Pa'zma'ny Pe'ter se'ta'ny 1/d. Budapest, Hungary, 1111
Phone +36 1 463 3883 Fax +36 1 463 3107 Internet http://www.bme.hu E-mail speechtech [at] bme.hu
BUTE develops TTS software for telephony circuit cards which it sells for use in IVR systems
Product MULTIVOX Languages generated Hungarian, Dutch, Esperanto, Finnish, German, Italian, Portuguese and Spanish Availability Hungary
Business Computer Projects
BCP House, 151 Charles Street, Stockport, SK1 3JY England UK
Phone +44 161 355 3000 Fax +44 161 355 3001 Internet http://www.bcpsoftware.com E-mail mail [at] bcpsoftware.com
Business Computer Projects develops TTS software for its logistics applications.
Product Accord Voice Languages generated English Availability Europe Business Computer Projects also develops speech recognition software.
Cepstral, LLC
1801 East Carson Street Second Floor Pittsburgh, Penn 15203 USA
Phone +1 412 432 0400 Fax +1 412 432 0406 Internet http://www.cepstral.com E-mail craig [at] cepstral.com
Cepstral develops TTS software for mobile devices
Product Swift Languages generated American English, British English, Arabic, Chinese, Canadian French, Italian, German, Japanese, Pashto, Mexican Spanish, Thai Availability USA, but distributed worldwide
Chunghwa Telecom Laboratories
Chunghwa Telecom Laboratories, formerly of Taipei, Taiwan, is no longer in business.
Conversay
15375 NE 90th Street Redmond, Wash 98052 USA
Phone +1 425 895 1800 Fax +1 425 636 0600 Internet http://www.conversay.com E-mail sales [at] conversay.com
Conversay develops TTS software for mobile devices and voice portals
Products Conversation Sever and Mobile Conversay SDK Languages generated American English, British English, French, German, Italian and Korean Availability USA, Europe, Korea Conversay also develops speech recognition software.
DSP Group
3120 Scott Boulevard, Santa Clara, Calif 95054-3317 USA
Phone +1 408 986 4300 Fax +1 408 986 4323 Internet http://www.dspg.com E-mail mcompton [at] dspg.com
The DSP Group develops TTS software for consumer telephony applications
Product Total Telephony Solution Languages generated American English Availability Worldwide The DSP Group also develops speech recognition software.
Ectaco Inc.
Ectaco Corporate Center, 31-21 31st Street, Long Island City, NY, 11106 USA
Phone +1 718 728 5334 Fax +1 Internet http://www.ectaco.com E-mail sales [at] ectaco.com
Ectaco develops TTS software for handheld devices
Products incorporated into Language Teacher Partner products line
Languages generated American English Availability Worldwide, via the Internet Ectaco also develops speech recognition software.
Elan Speech
Elan Speech has been acquired by the Acapela Group.
Electrel
Electrel, formerly of Bieville-Beuville, France, is no longer in business.
E-RHETOR
Michalakopoulou str, Athens, Attica GR-11527, Greece
Phone +30 210 7774936 Fax +30 210 7774936 Internet http://www.e-rhetor.com E-mail info [at] e-rhetor.com
E-RHETOR develops TTS software for mobile and network applications
Product PhonAesthesia Languages generated Greek Availability Greece
E-speech
448 Cherry Hill Road, Princeton, NJ USA
Phone +1 908 604 6500 Fax +1 908 604 6661 Internet http://www.espeech.com E-mail info [at] espeech.com
E-speech develops TTS software for various applications
Product Text-to-Speech Synthesizer and Text-to-Phoneme Translator Languages generated American English, Mandarin and South American Spanish Availability USA
Fluency
Prins Hendrikkade 159a, 1011 TB Amsterdam, Netherlands
Phone +31 6 14502731 Fax +31 Internet http://www.fluency.nl E-mail info [at] fluency.nl
Fluency develops TTS software for multimedia, internet and telephony applications
Products Fluency TTS, Spika Languages generated Dutch Availability Netherlands, Belgium
Fonix
9350 South 150 East, Suite 700, Sandy, Utah 84070 USA
Phone +1 801 553 6600 Fax +1 801 553 6707 Internet http://www.fonix.com E-mail sales [at] fonix.com
Fonix develops TTS software for IVR systems
Product FAAST TTS 5.2 Languages generated American English, British English, Dutch, Finnish, French, German, Icelandic, Italian, Norwegian, European Spanish and Swedish Availability USA, China, Australia, Europe, Japan and Korea Fonix also develops speech recognition software.
Force Computers
Force Computers, formerly of San Jose, Calif USA, is no longer in business.
Gdata Software AG
Gdata no longer develops text-to-speech software
GVZ Speech Technologies
Ünalan Mah. Ayazma Cad. Çamlica Is merkezi B blok Kat:2, 81190, Istanbul, Turkey
Phone +90 216 556 1530 Fax +90 216 556 1188 Internet http://www.gvz.com.tr E-mail info [at] gvz.com.tr
GVZ develops TTS software for telephony and PC applications and mobile devices.
Product GVZ-TTS 2.0 Languages generated Azeri, American English and Turkish Availability Turkey and the USA GVZ also develops speech recognition and voice authentication software.
HTK
HTK of Ipswitch, UK and not to be confused with the product of the former Entropic company of the same name, no longer develops text-to-speech software.
IBM
Research Triangle Park, North Carolina 27709, USA
Phone +1 317 554 7910 Fax +1 317 554 7968 Internet http://www-306.ibm.com/software/info1/websphere/index.jsp?tab=products/mobilespeech E-mail [Vendor has not provided a general e-mail address]
IBM develops TTS software for telephony-based applications
Product IBM WebSphere Voice Server 2.0 Languages generated American English, British English, Chinese, French, German, Italian, Japanese and Spanish Availability Worldwide IBM also develops speech recognition and VoiceXML software.
InfoTalk
Unit 507, Tech Centre, 72 Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong
Phone +852 2190 9600 Fax +852 2788 2306 Internet http://www.infotalkcorp.com E-mail info [at] infotalkcorp.com
InfoTalk develops TTS software for IVR systems
Product InfoTalk-Speaker Languages generated Mandarin, Cantonese and English. Availability China, Hong Kong, Singapore and Taiwan InfoTalk also develops speech recognition and voice authentication software.
Institute for Language and Speech Processing
Artemidos 6 & Epidavrou, GR-151 25 Maroyssi, Greece
Phone +30 210 6875324 7 Fax +30 210 6856794 Internet http://www.ilsp.gr E-mail support [at] ilsp.gr
The Institute for Language and Speech Processing develops TTS software for PC-based applications for the visually disabled.
Product Ekfonitis+ Languages generated Greek Availability Greece
JustSpeak
JustSpeak, formerly of Naples, Fla USA, is no longer in business.
Lernout & Hauspie Speech Products
Lernout & Hauspie, formerly of Ieper, Belgium, is no longer in business, intellectual property acquired by Scansoft which subsequently acquired Nuance and renamed itself Nuance Communications.
Loquendo SpA
Via Nole 55, 10149 Torino Italy
Phone +39 011 757 6111 Fax +39 011 757 6909 Internet http://www.loquendo.com E-mail info [at] loquendo.com
Loquendo develops TTS software for telephony applications
Product Loquendo TTS Languages generated Italian, Catalan, American English, British English, French, German, Greek, Brazilian Portuguese, Argentinian Spanish, Castilian Spanish, Chiliean Spanish, Mexican Spanish and Swedish Availability Europe, North America, and South America Loquendo also develops speech recognition and voice authentication software.
Lucent Technologies
Lucent Technologies has been acquired by Alcatel, subsequently renamed Alcatel-Lucent.
Matrubhasha
68 Electronics City, Bangalore 560100, Karnataka, India
Phone +91 80 852 3300 Fax +91 80 852 2590 Internet http://trinetra.ncb.ernet.in/matrubhasha E-mail matrubhasha [at] ncb.ernet.in
Matrubhasha develops TTS software.
Product Bhaashan Languages generated Hindi Availability India
Mindmaker
PO Box 506, Placerville, Calif 95667 USA
Phone +1 408 467 9200 Fax +1 408 467 9202 Internet http://www.mindmaker.com E-mail president [at] mindmaker.com
MindMaker develops TTS software for telephony and mobile applications and speech-enabled Internet sites.
Product FlexVoice Languages generated American English, Hungarian Availability USA, Hungary, Singapore, UK Mindmaker also develops speech recognition software.
NeoSpeech, Inc.
2051 Landings Dr Mountain View, CA 94043 USA
Phone +1 650 961 8838 Fax +1 650 961 8839 Internet http://www.neospeech.com E-mail richard.metzler [at] neospeech.com
NeoSpeech develops TTS software for embeded devices, PCs and telephony applications.
Product VoiceText Languages generated American English, Japanese, Korean and Mandarin Availability USA
NTT
NTT Cyber Communication Laboratory Group 1-1 Hikarino-oka, Yokosuka-shi, Kanagawa, 239-0847 Japan
Phone +81 486 55 2036 Fax +81 486 55 1104 Internet http://www.ntt.co.jp/cclab/e/index.html E-mail ckoho [at] lab.ntt.co.jp
NTT develops TTS software for voice portals, CTI and ITS systems.
Product FinalFluet Languages generated Japanese and English Availability Japan NTT also develops speech recognition software.
Nuance Communications
1 Wayside Road, Burlington, Mass 01803 USA
Phone +1 781 565 5000 Fax +1 781 565 5001 Internet http://www.nuance.com E-mail info [at] nuance.com
Nuance develops TTS software for telecom, automotive, mobile and PC/multimedia applications, and IVR systems
Product Nuance Vocalizer Languages generated American English, UK English, Dutch, French, German, Italian, Norwegian, European Spanish, Swedish Products RealSpeak, SpeechSecure, rVoice Languages generated American English, British English, Singaporean English, Australian English, Cantonese, Hong Kong Cantonese, Danish, Dutch, Belgian Dutch, French, Canadian French, German, Greek, Italian, Japanese, Korean, Japanese, Mandarin, Taiwanese Mandarin, Norwegian, Polish, Portugese, Brazilian Portugese, Russian, Spanish, American Spanish, Mexican Spanish, Swedish Availability USA, Australia, Brazil, Canada, China, Northern Europe, Southern Europe, Japan, Singapore and the UK Nuance also develops speech recognition, voice authentication and VoiceXML software.
Prologix Software Solutions Pvt. Ltd.
8th K.M., Faizabad Road, Ismailganj, Lucknow, 226016, India
Phone +91 522 309 7514 Fax +91 522 272 1381 Internet http://www.prologixsoft.com E-mail contact [at] prologixsoft.com
Prologix develops TTS software for IVR systems.
Product Vaachak Languages generated Hindi Availability India Prologix also develops VoiceXML software and a PC-based telephone system .
Rhetorical Systems
Rhetorical Systems has been acquired by Scansoft which subsequently acquired Nuance and renamed itself Nuance Communications.
Ricoh
7th Floor, Tomin-Nissei-Kasugacho Building 1-1-17 Koishikawa, Bunkyo-ku, Tokyo 112-0002, Japan
Phone +81 3 3815 7261 Fax +81 3 3818 0348 Internet http://www.ricoh.com E-mail www-admin [at] ricoh.co.jp
Ricoh develops TTS software for screen-reader software for blind persons
Product YUBEN-KA Languages generated Japanese Availability Japan Ricoh also develops speech recognition software.
Rubidium
PO Box 2099 8 Hasadna St. Raanana, 43000, Israel
Phone +972 9 7451412 Fax +972 9 7451418 Internet http://www.rubidium.com E-mail info [at] rubidium.com
Rubidium develops miniature footprint TTS software and chips for telephone caller ID name announcement and SMS announcement.
Product Rubidium Dialog Engine Languages supported American English Availability China, Hong-Kong, Japan, Taiwan, Western Europe and the USA. Rubidium also develops speech recognition software.
Sakhr
FreeZone, Nasr City, PO Box 5189, Cairo 11771 Egypt
Phone +202 274 9929 Fax +202 274 0055 Internet http://www.sakhr.com E-mail int_sales [at] sakhr.com
Sakhr develops TTS software for telephony applications
Product Sakhr TTS Languages generated Arabic, Egypt Availability Egypt, Kuwait, Saudi Arabia, UAE, USA Sakhr also develops speech recognition software.
Sakrament
Vostochnaja St.131, 220113, Minsk, Belarus
Phone +375 17 284 0650 Fax +375 17 284 0650 Internet http://www.sakrament-speech.com E-mail office [at] sakrament-speech.com
Sakrament develops TTS software handheld devices, device control, telephony and automotive applications and aids for the blind
Products Sakrament TTS Engine and Sakrament Speech Box Languages generated Belarusian, Russian and Ukrainian Availability Republic of Belarus, Russia, other CIS countries and Baltic States Sakrament also develops speech recognition software.
ScanSoft
ScanSoft acquired, and subsequently renamed itself, Nuance Communications.
Sensory
1991 Russell Avenue Santa Clara, Calif 95054-2035 USA
Phone +1 408 327 9000 Fax +1 408 727 4748 Internet http://www.sensoryinc.com E-mail sales [at] sensoryinc.com
Sensory develops TTS software for embedded applications such as automotive navigation systems, PDAs/convergence products, devices for the disabled and text readers.
Product Fluent Text-to-Speech Technology Languages generated English, German, Italian, Japanese, Mexican Spanish and Castilian Spanish Availability USA, Australia, Brazil, Hong Kong, China, Switzerland, Germany, India, Israel, Italy, Japan, Korea, Mexico, South Africa, Singapore, Taiwan, UK Sensory also develops speech recognition and voice authentication software.
SoftVoice
11301 W. Olympic Blvd., Suite 347, Los Angeles, Calif 90064, USA
Phone +1 310 948 5548 Fax +1 310 390 3215 Internet http://www.text2speech.com E-mail sales [at] text2speech.com
SoftVoice develops TTS software for Linux- and Window-based PC applications, embedded applications and IVR systems.
Product SoftVoice Languages generated American English and Spanish Availability USA, worldwide via the Internet
Speech and Software Technologies (I) Pvt. Ltd
3rd Floor, Ceebross Arcade, 1, 3rd Cross Road, Kasturibai Nagar, Adyar, Chennai, 600 020 India
Phone +91 44 2454 0370 Fax +91 44 2454 0374 Internet http://www.sstil.com E-mail sales [at] sstil.com
Speech and Software Technologies develops TTS software for telephony applications.
Product Text-to-Speech Languages generated Indian English Availability India Speech and Software Technologies also develops speech recognition software.
SpeechArabia
CP 364, 1211 Geneva 19, Switzerland
Phone +41 22 788 3367 Fax +41 XX Internet http://www.speecharabia.com E-mail info [at] speecharabia.com
SpeechArabia develops TTS software for PC-based applications.
Products Speech Bar, Read for Me, eMail Companion, Language Learning