At first, just before a fight begins one dog will raise their hackles up, standing still stiff and stare at the other dog.
Fighting has a lot of growling and yelps from real bites.
When one dog displays fighting but doesn't obey to the other dog which displays 'non-fighting' body language, this is what I call a one way or one dog fighting. This is very improper dog behavior and he or she needs to learn through training that this isn't the proper why to treat an another dog. However, a dog that displays fear aggression behavior toward the other dog which wants to fight then this is different. Growling is normal during play. My female German Shepherd mix tends to growl more than my male Labrador Retriever because she is just more vocal in general.