I pronounce
Annabel and
Annabelle the same - ANNA-bell.
Annabella is anna-BELL-uh for me.
I prefer
Annabel to
Annabelle and
Annabella. It's one of my top names, actually.
Annabel makes me picture a dark-haired, quiet girl.
Annabelle and
Annabella are much more frilly and make me think of a Southern belle type of girl.
I've never met anyone named Annabel/Annabelle/Annabella.
I personally would call an
Annabel "
Anna" if I had one, just because I really love
Anna. I don't know that people would do it automatically, though.