We always know when the mailman comes (I should say 'mail deliverer' since it could be a woman) because our dog, Brigit barks when he or she is on our porch.
Brigit didn't bark for 3 years after we adopted her as an abused dog.
But she found her voice a few months ago.
I hate the sound, but I'm so, so glad she thinks she's safe enough to bark....