Tolkien's descriptions suggest:
* A howl: Wargs are described as howling in several instances, usually in a menacing or predatory manner.
* A growl: Tolkien occasionally uses the word "growl" to describe the wargs' vocalizations.
* A snarling or barking sound: The wargs are often depicted as ferocious, suggesting a guttural, animalistic sound akin to a snarling dog.
Drawing from real wolves:
* Howls: Wolves are known for their haunting howls, often used for communication and territorial displays.
* Growls: Wolves growl to express aggression, warning, or dominance.
* Yips and barks: Wolves also use yipping and barking sounds for a variety of social interactions.
Considering these factors, we can imagine a warg's sound as a combination of:
* A deep, guttural howl, possibly more menacing and guttural than a wolf's.
* A fierce, growling sound, conveying aggression and threat.
* Short, sharp barks or snarls, used for warning or communication with other wargs.
Ultimately, the sound of a warg is up to your imagination, but these elements can provide a starting point for your own interpretation.