Thanks to Laura Fullton, I have a clearer fix on vocal fry. Laura found the very interesting work by Ben Trawick-Smith on the topic.
Ben calls it a “creaky voice” and asks 1) whether this vocal technique might have a special connection to the Pacific Northwest, and 2) whether it passed through this connection, and the rise of alternative music there, into general usage.
In fact, this speech trait seems almost de rigeur among the alternative music set. You could almost hypothesize it began as a regional quirk, then spread through the burgeoning indie rock movement. Evidence of its indie inter-regionalism? Musician Justin Vernon (aka Bon Iver) has creaky voicing, even though his dialect otherwise betrays his place of upbringing (northern Wisconsin):
This pushes our time-line back and de-genders the vocal fry. (Assuming of course that “creaky voice” and “fry” are connected…and this might be wrong.) The data thicken!
(I am filing this post from 32,000 feet and I only bought 30 minutes of access. So I have to post now!)