Hi Marvin,
In terms of interpreting diagrams, you may want to check out the vOICe from
www.seeingwithsound.com.
I have managed to create certain flow diagrams with Microsoft visio 2003
but, from the below message, I suspect you need something far more
sophisticated. Will Pearson who was on this list was working on a drawing
program for the blind.. You may want to contact him and see if he can help.
Pranav