Now that Debian Jessie is out and the net install CD gives the option of a number of desktops, I've been trying some for accessibility.
Without much hope I tried Cinnamon and KDE. Both are totally silent.
For KDE I don't know if there is something else that needs to be installed, like qt-at-spi or something. But I assume, and that is not always very wise, that the Debian team would have included that.
Next I'll try XFCE. I know LXDE is at least partly accessible but Mate feels so snappy I'll stick with that as my working desktop.