Barking usually begins as a puppy starts to mature but some puppies yap and bark earlier. Some dogs are always quiet. Typically, humans want their dog to alert them when something important or urgent is happening but then they also want them to be quiet and not disruptive. Dogs bark for several reasons; for attention, as a warning, fear, excitement, territoriality, etc. The best way to prevent barking from becoming a problem is to have a dog barking training plan and procedure in place that will help you communicate with your dog as to when and where not to bark.