I disagree that dogs want to "talk" to us. They want to communicate with us, and do this by subtle body language, which we ignore (because we don't see it) but when a dog barks, it is to get our attention because we haven't taken notice before. A barking dog is essentially shouting because we wouldn't listen. If we read our dog's body signals correctly, then a dog has no need to bark. Wolves and dogs very rarely bark in the wild. Barking has only become more usual dog behaviour as they have become domesticated.