Most dogs bark because they are bored and/or they want attention.
Unintentionally you have probably brought this upon yourself.
Yes it's true.
Answer these few quick questions to yourself.
1.
Do you spoil your dog? 2.
Are your constantly hugging, cuddling, and petting your dog? 3.
Does your dog have more toys than you did growing up? If you answered yes to any of those questions, chance are you set yourself up.
You see dogs love attention, it's in their nature.
When your dog was a puppy he quickly learned when he barked he got fed, a drink, petted, played with, or even yelled at.
Even yelling at a dog is enough to satisfy their attention need.
So to them, barking equals results.
So here is what you need to do.
Get your dog into a routine.
Your dog will eventually learn when he goes outside, when he comes in, when he is fed, played with, and when to sleep.
Reward your dog for being quiet.
When he is barking tell him to "Stop" or "Quiet".
When he has remained silent for a few seconds reward him with a treat and praise him for being a good dog.
One secret is to dash your dog in the face with a little water when telling him to stop or be quiet.
Dogs don't really like that and will quickly realize why they are getting splashed in the face - because they were barking.
Within a few days of applying the above your dog should become a well behaved and most importantly to you and your neighbors, a quiet dog.
Additional resources on how to stop your dog from barking