W3C:

2008-03-17: The Voice Browser Working Group has published an updated Working Draft of Speech Synthesis Markup Language (SSML) Version 1.1, part of the W3C framework for enabling access to the Web using spoken interaction. SSML provides a rich, XML-based markup language for assisting the generation of synthetic speech in Web and other applications. It provides a standard way to control aspects of speech such as pronunciation, volume, pitch, rate, etc. across different synthesis-capable platforms. See the list of changes in this draft and learn more about W3C’s Voice Browser Activity. (Permalink)