Dogs don't use a vocal range like we do, for instance when we get angry we deepen our voice or even shout. Dogs communication is a lot more simply than that so let me categorize the different sounds for you. Before you read on have a guess to see how many you know all ready and what you think they mean.... 
Infantile Sounds - Cry, Whimper and Whine.

Warning Sounds - Bark and Growl.

Eliciting Sounds - Howl.

Withdrawal Sonds - Yelp.

Pleasure Sounds - Groan not to be mixed up with a growl.

My Tip..! Never reward your dog by using your voice when they are displaying warning sounds. ie; Barking in the garden, your dog will keep barking or bark to get attention because your voice alone is a reward for that behaviour..! Investigate infanile sounds and Eliciting sounds.