We've had 3 shepherds over the years.
The first was a female who used to lounge on an old couch next to the french windows on the sun porch to watch the world go by. She would bark when someone came to the door, and particularly aggressively if it was the mailman and neighbors' dogs who had the nerve to urinate in front of the house. On walks, particularly at night, if she had her suspicions about an oncoming person, I could feel an inaudibly low growl vibration through her leash, but otherwise she didn't make a sound other than 'pay-attention-to-me' barks when at the park.
Our second was a male who was timid as a pup and compensated for that by being over protective as an adult. In the yard he would bark aggressively, showing his teeth, at any person or animal as long as they were within 25 feet of the fence. The same in the house if anyone was even close to the door. He would also howl to echo police, fire or ambulance sirens. But, if not in 'protect mode' or singing with the sirens he was quiet.
Our current one is also a male who barks at the sound of the doorbell and if 'on duty' parked by the french doors surveying the street, will bark at anyone approaching the door and other dogs being walked past the house (these last barks quickly turn into half-hearted woofs of "yeah, yeah, I'm here and I see you" that will last for maybe 1 minute). Around the house, he will stop if I say "enough." On the other hand, he will bark with enthusiasm the minute he sees me pick up a poop bag and head for his leash (and won't stop until I get it). There are also the occasional 'pay-attention-to-me' barks when he wants to play, particularly at the park. They stop when I say "no."
Of the 3, the 2nd was the noisiest and also the least confident (see post #4). Of the 3 both the first and current one were at the head of the puppy pack to see who we were when we visited the breeders to pick out our pups (always a good sign of confidence). The 2nd hung back.
All that said, as others have already said, shepherds are also very talkative (and in my limited experience, particularly the males). It's as if they figured out that human speech communicates what we want from them and they're going to try their hand at it with us. All 3 would come to us with "Timmy's in the well" imploring whines whenever they wanted something, not to mention whines of joy when we got home from work after leaving them alone during the day. And it's not just our dog(s). My wife and I went to a dog park membership meeting a couple of years back and about 30 minutes into it we hear this god-awful whining from the back of the room that sounded like someone was ripping the heart out of a dog. We looked at each other, smiled and she said "shepherd." Sure enough, we turned around and someone had brought a pair to the meeting and the male was letting everyone within earshot know he wanted something (I'm guessing to get out of the room).
Can't forget the most important part. All 3 were wonderful dogs. Shepherds are the best.