YOH

[Michael Newman]

Frank McCourt mentions a usage of 'yo' among stable hands to call
horses in the 1940s, I think. Its vocative use might have spread from
there.

Currently, it maintains that use among almost all young New Yorkers.
It is also used by many as a kind of emphasis marker (I'm not sure of
the technical term here-not my area) not unlike the Straights English
"la-" or for that matter the peninsular Spanish "tio" or Mexican
"guey" which also share vocative uses.

e.g. That Falwell's such a fool, yo.

In that usage the 'yo' is downstressed.
--
Michael Newman
Assistant Professor of Applied Linguistics
Dept. of Linguistics and Communication Disorders
Queens College/CUNY
Flushing, NY 11367