Bella definately seems to dream - they must be able to dream or all of this behaviour is very strange
We love listening to her snore (sad I know :
: ) and she is often heard yelping or that voice they do that sounds like they're trying to talk, she's also growled once or twice and her legs are often moving about as if she's running, bless
I tend to just make a little noise, maybe a low whistle, or gently stroke her if she's beside me - not enough to wake her but it justs seems to settle her a little bit.
One night, she was really yelping and she was downstairs in her crate, although it was quite a stong yelp is was sort of quiet, kind of under her breath, so we figured she was dreaming and didn't go down to disturb her.