Is there a comprehensive list of known APIs for desktop or browser environments?
I'll rehash and update an answer from How can i do speech recognition in C or Java or PHP?. This is by no means comprehensive, but it might be a start for you
From watching these questions for few months, I've seen most developer choices break down like this:
Windows folks - use the System.Speech features of .Net or Microsoft.Speech and install the free recognizers Microsoft provides. Windows 7 includes a full speech engine. Others are downloadable for free. There is a C++ API to the same engines known as SAPI. See at http://msdn.microsoft.com/en-us/magazine/cc163663.aspx. or http://msdn.microsoft.com/en-us/library/ms723627(v=vs.85).aspx. More background on Microsoft engines for Windows What is the difference between System.Speech.Recognition and Microsoft.Speech.Recognition?
Online service - Nuance, Yapme, ispeech.org, vlingo, others. Nuance has improved their developer program and will now give you free access to their services for development. Yap (I believe) was recently purchased by Amazon, so we may see some changes there.
Of course this may also be helpful - http://en.wikipedia.org/wiki/List_of_speech_recognition_software
There is a Java speech API. See javax.speech.recognition in the Java Speech API http://java.sun.com/products/java-media/speech/forDevelopers/jsapi-guide/Recognition.html. I believe you still have to find a speech engine that supports this API. I don't think Sphinx fully supports it - http://cmusphinx.sourceforge.net/sphinx4/doc/Sphinx4-faq.html#support_jsapi
There are lots of other SO quesitons: Need text to speech and speech recognition tools for Linux and pyspeech (python) - Transcribe mp3 files? which talks about http://code.google.com/p/pyspeech/. You may also want to look at http://code.google.com/p/dragonfly/
The leading API vendors of text to speech (voice generation) are YAKiToMe! and iSpeech. YAKiToMe! is the one I use because I like their voice quality the best and they're the least expensive (mostly free). They support male and female speakers in multiple languages. Some of the voice vendors, like Acapella, Nuance, Loquendo and iVona have decent voices but tend to be expensive to use.
Here is how you can do it: Note: it is an api from google, so it only works in chrome browser.
(See live demo and download full source code here http://purpledesign.in/blog/?p=33)
define a button
The speech is written in the textarea