The vocalisations of dogs help other dogs – and human, to better guess their emotions. However noises in conjunction with tail movement is a better guide!
Barks– These can be a reaction to a perceived intruder, hearing a random noise or express a multitude of emotions including loneliness, fear, suspicion, stress, and pleasure. Playful or excited barks are often short and sharp, such as when a dog is attempting to get a person or another dog to play.
Growling – Growls can express aggression, a desire to play, or simply that the dog wants something to stop. Apparently – although I wouldn’t recommend testing this, for a serious threat the dog will start off with a very low toned but strong growl, if this threat is ignored then the tone of the growl will get higher in tone.
Howling – 2am “hello world” noise. Long-range communication.
Whining – A high-pitched vocalisation, often produced nasally with the mouth closed. A “want” noise. A very insistent dog may add a bark at the end of a whine, in a whine-bark, whine-bark pattern.
Whimpers or yelps – Pain or distress. Whimpers are often associated with the lowering of the tail between the legs. Whimpers can also indicate strong excitement when a dog is lonely and is suddenly met with affection – such whimpering is often accompanied by licking, jumping, and barking.