State of Speech Synthesis and Text-To-Speech?
Gnulix asks: "Are there any, preferably either open source products available that produce realistic speech from an arbitrary (English) text? Projects such as Festival doesn't sound all that much better than SAM (Software Automatic Mouth) did on a Commodore 64 back in 1979, nor does SoftVoice's or IBM's new products sound very good. I mean we all know that Stephen Hawking is a fun loving guy, but I bet you that he didn't choose his unrealistic, robotic voice just for the heck of it. With all the amazing advances we have seen in real-time graphics, shouldn't speech synthesis have come much, much further than what is, seemingly, available today?" Ask Slashdot last handled the Voice-To-Text issue in January of this year.
is the best Text to speech conversion program
checkout http://www.naturalvoices.att.com/
Another extremely strong competetor to Natural Voices is Speechwork's Speechify. Take the "Speechify Challenge" -- it's still possible to tell which is a real recording and which is the computer, but it is very difficult. Some say it's the best engine available, but I guess that's a matter of personal preference.
I don't know about Open Source TTS, but the commercial versions (AT&T, Speechworks, and others) are sitting on the threshold of truly natural speech. I work in the speech industry, so I follow progress and have seen some of the unreleased demos of upcoming versions. In the next couple years, we can expect amazing things. It won't be long before the Speechify Challenge will truly be impossible to beat.
By the way, for those of you who don't know, the newest and best-sounding engines don't use purely synthesized sounds as older and small-footprint engines do (Festival and Steven Hawking). The engines are built using actual recordings: a "voice actor" will sit in a studio and record dozens of hours of speech, and then, over the course of several months, the recordings are then cut and spliced into individual phonyms, which are reassembled by the engine. This means that the voices actually sound like real people, and the only unrealistic part is the inflection when generating complete sentences. You can order custom voices (for several tens of thousands of dollars) and get a voice that sounds identical to that of your celebrity of choice.