CSS3 Speech module is now in last call state (Aug 18 , 2011) . Journey for making accessible web standards have come far from WCAG guidelines , SSML (Speech Synthesis Markup Language ) to CSS Speech
Here is the summary of what CSS Speech module provides.
CSS Speech standard specifies how to present the content in way which can be understood by speech synthesizers. Using CSS Speech module we can specify meta data like voice speed , pause information etc for content . This CSS information is used by User agents while rendering and producing final sound output for the content.
Typical usage for this would be Screen readers
Machine to Human interaction ( e.g incase while you are driving car , car would read content for you online with appropriate pauses , breaks etc or your ebook reader will read the book , exactly the way it is read by humans)
CSS Speech is based on concept of Aural Box Model for content to be rendered in speech form . It is a conterpart for visual box model for visual presentation of content.
See the Visual box model for CSS and Aural Box Model below for similarities
The analogy between Visual Box model and Aural Box model is as follows
padding >>>> rest
border >>>>> cue
margin >>>>> pause
Cue : Cue is small piece of sound which you can insert in between.
Some of Properties and Characteristics which are available include
The link below provides the complete summary for each of the above properties
Sample code snippets
Explanation for Code snippet
The user agent of end user will read the webpage paragraph with female voice , left channel etc.
You can send your feedback for the last call to W3C , its open till Sept end.