If your dog is not well socialized, take the time to introduce him to your neighbors and other visitors such as postal carriers or delivery personnel. When visiting neighbors don't want to pet or visit with your dog, crate him or put him in a nearby room behind a baby gate. Teach your dog that it is normal to accept some strangers on your property occasionally. Barking or vocalizing is also a common behavior about which a neighbor may complain. If left outdoors, unattended for long periods of time, then your dog's noise may be a problem.
Dogs are social animals who require companionship.
When left by themselves, they frequently make noise to get the human attention they need. Don't let your dog languish alone in your yard. Do the necessary work and train your dog to live in the house as part of the family. Avoid letting your dog out late at night or early in the morning if possible. What may be music to a dog owner's ears, may be nerve-wracking noise to a neighbor.