Murphy has always been a big barker. If anything moves outside--cat, deer, dog, person, drone, etc.,--he sounds off with an authoritative and aggressive yet repetitively monotonous barking.
Belle, on the other hand, was so quiet when she got here that I thought that maybe the barker was optional on that particular model year of Shepherd. It was weeks before I ever heard the most hesitant attempt at a bark come out of her mouth.
But after hanging around with her big buddy for these past few months, she's now right in there with him, albeit with a higher-pitched, faster bark. She follows him around and when something sets him off, she keys in on it too and emulates him like a student copying her master.
Now when anything moves outside, it's "WOOF! WOOF! WOOF!" and "Yark! Yark! Yark! Yark! Yark!" as they sound off together in two-part harmony that can be heard a block away when they are out on the deck.