It depends as proving your intention to provoke them into this can be non-protected speech under fighting words doctrine if Bob knew it would specifically provoke Dave to violence. If Bob instigated the altercation under these circumstance (both knowing and intending to provoke Dave to violence) he may be looking at his own assault charge. This would be especially true if Bob was threatening Dave with violence, prompting the outburst.
Since no indication of what was said, under U.S. Law speech is always assumed protected until proven otherwise, so self-defense would be a viable defense to killing Dave, assuming Bob was saying provokative, but not personally insulting or threatening things looking to get a reaction from Dave. Again, the context of the taunt, not merely the words said, are critical so the answer can't be provided without the offending statement. As a general rule, the general jurisprudence errs on the assumption that Dave should have been mature enough to handle the insult without resorting to violence.
Stand Your Ground plays little importance in the scenario other than removing the question of "Duty to Flee".
If this was a successful self-defense, Bob would not be sentanced. If not, he could be give assault to murder chargers depending on the nature of how it went down. In either situation, nothing justifies Dave's violent reaction to the taunt so were he to survive, he'd likely get punished for assault and battery up to and including 1st degree murder, though 2nd degree might also be more likely to sway the jury.
It should be pointed out that Assault can happen without actually physically harming someone. Assault is merely the threat of physical violence or acting in a manner to convey such a threat. Battery is a seperate charge for actual physical violence.
This is also a 30,000 feet overview as a more specific description of the scenario could give a more percise answer.
