I wrote an article on this topic, and attached to it advice on Information Operations and using an interpreter. It was Afghanistan specific. Infantry Magazine published it, but it is easier just to follow the link to my blog at the end.

Even better than my ramblings is the bibliography I included at the end. One of the articles I mentioned specifically mentions negotiating in shuras and is very much along the lines of jcustis's initial advice.

I will say profanity and yelling should never enter a shura. Ever. Even after multiple attacks in your AO with a strong suspicion a village knows about it. Why? Because yelling is bad in American culture, and worse in Pashtun culture. Can you imagine a board meeting that ended up with one side yelling at everyone? Or a city council meeting where a foreigner came in and berated the board? I can, but in each case it would be a bad thing. Yelling--from either side--is usually a sign of superiority and a sign of division. It is a sign that that is a dysfunctional group. For instance, think of congress when a bunch of members are yelling at each other, that is a sign that not much is getting accomplished. If you have to yell at local Afghans you probably lost control. (Much like everyone has that boss who yells and screams, and everyone thinks he is a sucky boss.)

I bring this up because on more than one occasion I have heard Soldiers or Officers above me specifically point to the "yell at the elders" TTP as an effective shura strategy.