Por un lado tenemos Using WAI-ARIA in HTML, que tiene como resumen:
This document is a practical guide for developers on how to add accessibility information to HTML elements using the Accessible Rich Internet Applications specification [WAI-ARIA], which defines a way to make Web content and Web applications more accessible to people with disabilities. This document demonstrates how to use WAI-ARIA in [HTML5], which especially helps with dynamic content and advanced user interface controls developed with Ajax, HTML, JavaScript, and related technologies.
Por otro lado tenemos el documento ARIA in HTML que es simplemente un working draft, y que tiene como resumen: