I recently released a new extension I created into PECL (pecl.php.net). This extension is called FliteTTS and it’s claim to fame is the fact it generates wave files based on strings you supply to it (aka a voice synthesis extension). I came up with the idea to make the extension after overhearing a conversation about audio capthas and the lack of solutions pre-existing for the task in PHP. The extension wraps the library from Carnegie Mellon University called Flite (http://www.speech.cs.cmu.edu/flite/) and the output quality is rather decent albeit a bit close sounding to the old school Dr. Sbaitso. I had previous experience with the Flite library from my work porting Hotscripts.com to PHP a couple years back, but Hotscripts uses a shell exec (aka bad performance) to generate the wave file from the app which is provided with the library. The extension version on the other hand is extremely fast and has a very tiny memory footprint. The API and functionality is still a bit in flux (thus the lack of an official PECL release), but the code is in CVS and is very useable. Flite can be a bit of a pain to get compiled, but once you do the extension is really simple to get compiled and you can be up and running moments later. Check the provided test cases for examples of how to work with it. If you have any questions, please feel free to leave a comment or shoot me an email.