If you are raising your voice, to assert control, to make your child fear you, imo it's abuse, regardless of the words you are coming out with. We all fall foul of it, occassionaly, but it is a form of abuse. I believe there has to be a tonal difference with your voice to identify the difference between 'normal business' and 'you've done something wrong', but rather than shout, form strong words are necessary from time to time.
I agree with @Karl Bielefeldt i.e yelling when there's been a bit of a loss of control, due to a long day, or for whatever reasons, doesn't constitute abuse, but is heading in that direction.
I think the links between verbal abuse and physical abuse (spanking etc) are that you are asserting control over someone by bullying them, making them submissive; for me it strangles creativity too, but that's a personal thing.
I have an article I read not long ago which I agree with, on almost all levels, about what constitutes the abuse you're talking about, be that teachers at school ridiculing kids who give the wrong answers or their coaches laughing at their perceived frailties, or weaknesses; it's all the same thing. Interestingly, the article links fear in the parents as one of the factors in why they verbally abuse.
I have strayed too far with my voice, but never the content; I'd be mortified if I called my child stupid, or weak, or useless. The most I have ever accused any of my children, was of being a bit sooky sometimes. Even then I felt bad.
My overwhelming belief, however, is that parents who try too hard to get their children to be submissive to them, and society generally, have control issues.
Anecdotaly, I have a friend whose father was a Sergeant Major in the army. He had 7 siublings. The father had control of a regient of men (some 600 soldiers), whom every one would crawl over broken glass for, would, literally and physically, die for. yet he couldn't control his kids. The father would beat the kids, at almost every transgression and eventually ended up having a breakdown.
The effects of verbal abuse