Well, first, yes if the guy can speak, he can breath. Second, we have no idea about the technique used. "choke hold" is very generic...RNC? Guillotine? hands on throat? Headlock? we just don't know. The guy may have died from unrelated or unknown medical issues. Maybe it was not a "choke" but something which injured his windpipe, etc. Not enough info to tell. We don't know how the other two were restraining him.
But, I doubt it would fly as murder as I doubt the guy intended to kill him. Manslaughter, maybe. If the guy was skilled or unskilled, we don't know.
Too little info to make an assessment really.
there was a case that happened in australia a couple of years ago where 3 bouncers held someone down for a few minutes, one guy applying a RNC. obivously, the guy died.
when this kind of thing happens i usually assume that the people involved had little to no training in a grappling art like judo or BJJ.
i've strangled a couple of people while doing security with no problems. they woke up soon after without a scratch on them. i actually think it's very safe if you know exactly what you're doing.
Rereading this again, it sounds like it was compression asphyxiation. He would have been able to say (or gasp) "I can't breathe" in that situation, at least initially. If you sit on someones chest/diaphragm long enough with enough weight, it limits the ability of the lungs to fill. The person eventually cease being able to breathe.
I would second that. Walmart Loss Prevention have killed people via compression asphyxiation before.