I'm the lead for the Orca Screen Reader project as well as the GNOME accessibility project in general. I've been involved in Making the X Window System Accessible to People with Disabilities for nearly 20 years, having helped create things such as:
AccessX - the good part of XKB.
The RAP - the Remote Access Protocol for the X Window System (the first service oriented approaches to accessibility for our platform, which led to the Java Accessibility API, which led to the AT-SPI)
Mercator - one of the first screen readers for the X Window System. My role was mostly working on RAP. The folks at Georgia Tech did the hard stuff.
I'm also the maintainer for gnome-speech, though the work I put into it is mostly for sustaining purposes. I'd like to migrate it off of Bonobo/ORBit someday and move it to something else (DBUS?), but I just don't have time.
Other things I've have led in the past include:
You can usually find me on the #orca channel on irc.gnome.org. Check out my band, too: Russell Hill. It's one of the most pleasant musical groups I've ever been in.
Willie Walker (irc.gnome.org nick -- WillieWalker)