The main reasons for their barking are excitement, territorial, anxiety, being young, illness, and boredom.
The most effective strategies are preventing barking situations from occurring, giving them plenty of exercises, providing treats to distract them from barking, socializing them with new people and other dogs, and providing proper training from a young age.
Possible Reasons for Your German Shepherd’s Barking
- Nerves or Fear
- He is Still Young
- Separation Anxiety
- Territorial Barking
Excitement is a usual factor for German Shepherds to bark.
When they sense some fun activity is about to start, they will bark to guarantee it happens.
For instance, they might bark when they listen to your footsteps coming towards the door, if the trainer is parking his car, if the dog walker is coming home, or you are giving signs that it is time to go for a walk with them.
2. Nerves or Fear
It is possible that the barking sounds are caused by your dog being anxious or afraid of something.
It is also possible that some incidents occurred in the past that your pet does not want to memorize, so they bark to stop their thoughts.
It might also be because it is afraid of going somewhere, like the vet, and giving you signals they do not want to go. 
Did you Know?
German shepherds lick their lips and tuck tail in between their back legs when nervous
3. He is Still Young
German Shepherd pups are known for barking a lot.
If your German Shepherd is quite small, it will begin to bark less as it matures.
That said, pet parents should begin training while they are still young since they will act more like a grownup, and you would be prepared to handle them whenever they bark.
German Shepherds are trained to be highly energetic canines that will perform difficult tasks with their people on a regular basis for several hours.
It implies that they must engage in a lot of physical activity.
They will become bored when they do not receive a sufficient amount of physical activity.
Whenever they are dissatisfied, they may become aggressive, and they will bark excessively, as they are seeking attention and entertainment. 
It might be the reason for your German Shepherd’s excessive barking if he is not receiving enough exercise.
You should provide them with enough exercises in order to keep them busy.
5. Separation Anxiety
Barking is among the most obvious indications that your German shepherd is dealing with separation anxiety. 
They might even growl, scrape, nibble on items, and engage in other harmful activities in addition to barking.
It is crucial to realize that their destructive behavior is not to hurt your feelings; they can not stop themselves from doing it because they are worried. 
If your German shepherd is experiencing anxiety issues, then you must seek guidance from a veterinarian.
Did you Know?
Proper and training and lots of exercises can avoid separation anxiety
6. Territorial Barking
Another reason German Shepherd dogs bark is to guard their territory or their humans.
This kind of barking might happen when visitors ring the doorbell or if you are in the presence of other animals and he shows aggression towards other dogs.
In some situations, they will even bark quite often if they sense something nearby or attack someone. 
The body language of a German shepherd may frequently reveal whether or not they are barking in some kind of aggressive manner.
You will observe they have elevated hairs on the back, for starters.
Besides that, they will approach the danger and may even jump at a higher level or against any window if they sense something.
It is also possible that your German Shepherd is barking because he is hungry.
This form of barking occurs when the dog is supposed to be receiving meals, for instance, during the morning.
You may rectify this by training your pet to sit down and only start eating after you instruct him.
It is possible that your German Shepherd has suffered an injury.
In such cases, he might be barking to alert everyone to the fact that he is in severe pain, or he might just be irritated.
You will probably notice other signs, including limping, and the howling will be spontaneous and in places where he would not ordinarily bark.
Also, several German shepherds might develop a brain disorder related to dementia while they get mature.
It can drive your dog to bark without any apparent reason, even though they have never done the same before.
Another possibility is that your dog may become blind, or get worse vision.
If you suspect any of the cases above, you should rush him to the veterinarian.
Note: Dementia can lead to behavior changes loss in memory in German shepherds. 
Did you Know?
German shepherds can even bite if you ignore them for a longer time
GSDs are not the type of canines that can be handled with force.
When you attempt to use power to handle them, they respond with aggressiveness.
If you notice that your German shepherd is barking excessively, then the first thing to stop is to figure out what is causing it.
After you have figured out what is causing it, you should work to prevent it with your best efforts.
Have some patience and understanding while you handle your pet’s barking behavior.