Documenting Historical Change in ASL

[Karlin, Ben]

Has anyone documented change in ASL over time?  Anyone got a reference?

AND the other question I promised:  Has anyone got documentary references
for rural southern black signs?  I learned sign in Chicago during the 80s.
Several of my acquaintances were rural southern black people (Deaf and
Deafblind) that came north in the migrations of the 40s.  Now that I am in
St. Louis I am often with folks with similar backgrounds.  I suspect some of
the signs that I know are not ASL exactly, but that rural southern black
version(? dialect? language?).

Ben Karlin, St. Louis, MO