Dogs bark at us to communicate that they want something. That might be food, attention, or to alert us to a danger. It can be difficult to know why our dogs are barking at us, but if you are able to identify what the cause of the barking you can try to address the issue to stop your dog from barking.
An angressive black and white adult dog barking
Dogs bark when they are scared, protecting their territory, in response to other dogs barking, if they are hurt, or when they want attention and a tummy tickle.