Spanish /rr/ (was Re: IPA / SAMPA question)

Carlos Thompson wrote:

>There is, of course, some dialectal variation, i.e. mountain dialects in
Ecuador and Southern Colombia (Peru?), pronounce /rr/ as [Z] or [z`].


Interesting!! And anywhere else, do you know?? Any idea how it originated??
That pronunciation also occurs in some provincial areas of Argentina; e.g.
in Tucumán I was told I could change money at [la'kasa 'ZeZes] and was
completely flummoxed until the lady pointed down the street to a sign,
REYES.  At cabarets etc. in Buenos Aires, comedians made fun of it.  Arg.
linguist-friends claimed it's not the same as the [Z] = |y, ll|, but has
still some kind of rhotic quality (maybe more retroflexed)-- they cited
Czech r-hacek as comparable. Anyhow, I couldn't produce the sound to their
satisfaction.