Re: Spanish ll in different dialects

>Does anyone know any other dialects that pronounce ll as j?  Or why
this is so?

Spanish  consonants in general vary more widely than the vowels
(rather the opposite of English in that respect), and <ll> may be the
most variant.  Depending on dialect it
is either a palatalized /l/ (/L/?)  or a full sequence /lj/; going the
other way, it can lose the lateral aspect entirely and gain varying
degrees of fricativization, yielding /j/, /Z/, or even /dZ/.

This is just the mechanism of langauge change at work.  All of those
were originally /l:/, hence the spelling, but the sound adapted to its
environment in different ways in different regions.

-Marcos