>> Could one use American Sign Language to talk over one's shoulder? <<

For some things, yes, but I've edited this for improved clarity. Sometimes it takes me a little while to adjust to new characters.

>> BTW, mother-in-law was telling me today about the work of Margalit Fox and Bedouin sign language - I bet that you and ysabet would both be fascinated. But you've probably read it already for work. :) <<

Cooooool. I have heard of the village, but not the book. Thanks for the tip; I've added it to my Amazon wishlist.