Because they are transliterating using a pronounced sound from within their brain, hence would have gets contracted to would uv.
Which to the mind's ear sounds like of.
This is why.
(
Jeru War and Piss,
Thu 29 May 2008, 2:22,
archived)
but then the brain should surely run it over
and think 'would of? how do you of? That makes no sense!'
(
hexachordal la la la la la,
Thu 29 May 2008, 2:24,
archived)