Ok, it seems there is also incompatibility with lightdm. The problem is that I don't think anybody has actually tested enabling accessibility after installation without accessibility enabled.
The safest would be to reinstall with accessibility enabled during installation. Using the real debian installer would be preferrable, since that's what was actually tested and documented. If you really want to work with the live image, it seems that it happens to include some accessibility. Unfortunately it doesn't support the documented shortcuts, so to enable speech, at the boot menu you need to press the end key and then enter. Samuel
