Taken from my first dog-group............
Dogs can't talk so they have their own way of communicating: Barks, Growls, Howls, and Whines.
The Bark:
A loud, repeated bark, sometimes accompanied by a growl or snarl: conveys aggression or dominance. ("Get away or I'll bite you!")
Sharp, short barks: alert to intruders or danger ("What? What? What?")
A light, high-pitched bark: an invitation to interact or play. ("Come play with me!")
A low moaning-type bark: signifies anxiety. ("Who's out there?")
Short, high-pitched yips: excitement, eagerness, friendliness, or curiosity. ("Hi! Hi! Hi!")
The Growl:
A deep, low growl emanating from the chest and progressing to a snarl: conveys aggression ("I'm warning you!")
A low, assertive growl: indicates dominance. ("Get out of my yard!")
A low, whining growl: shows worry or fear. ("Please don't come any closer!")
Soft, low growling: a play signal. ("I've got the ball. See if you can take it!")
The Howl:
A long, sustained rising howl: usually conveys fear or anxiety, as with a dog left alone. ("Where are you? Come back!")
A short, happy howl: indicates an emotional greeting. ("Wow! It's great to see you!") This howl is common with northern breeds such as huskies.
A "bay": the howl of a hound at chase ("We've spotted the fox!"); a victorious howl ("Come on! We've found it!").
A sustained howl in unison with the sound of a siren ("Must be something to wail about.") or a musical instrument or a choral pack response. ("For we are jolly good fellows!")
The Whine:
A long whine, rising in pitch: indicates anxiety or fear. ("I'm scared!")
A low whine: serves as an alert. ("Listen, something's out there!")
A short, worried whine: can take place during flight. ("Leave me alone, leave me alone!")
Low, worried whining: indicates submission or subordinate rank. ("Don't hurt me. I surrender.")
Short, eager whines: curiosity, excitement, or an invitation to play. ("Come on! I can't wait!")
A screaming whine: used when a dog is being beaten by a dominant dog. ("Please! I can't take any more!")
A loud, screaming whine: indicates pain or injury. ("Stop! It hurts!")