Answer:Lack of Socialisation - Dogs that haven't had exposure to people during their early stages of development are more prone to barking at visitors. Territorial Instincts - Dogs have a tendency to be territorial. They consider your home as their space. When a stranger comes in, they naturally feel the need to establish their authority and guard what belongs to them. Barking is their way of expressing this urge to protect their territory.Excitement - Sometimes our canine companions are so overwhelmed with excitement to see a new face, that they bark at the sight of strangers approaching them.Alarm barking - This is similar to territorial barking, where your dog sees something that it thinks is unusual, so it feels the need to let everyone know. It could be that someone is coming to your door, or your neighbor is getting in their car. It could even be that there’s a bird in your garden. Fear - Unfamiliar people or animals, new environments, or unknown noises can trigger a dog to bark in response to a perceived threat.Territorial barking - is similar to alert barking. Your dog is responding to the presence of someone or something near their home. Territorial barking intends to protect the area and make the "intruder" leave the premises. While alert barking might stop after you've been made aware of what's happening, territorial barking usually lasts longer — until the perceived threat is gone.Diverting attention in public - When you go on dog walks, a lot of people may want to engage your dog if they bark off in a nonthreatening and excited manner. You don’t have to reward your dog for barking for attention.