Is she tied out on the choke collar?
Is she having trouble barking or just less disturbed that there are visitors?
If she is tied out on that then she may have injured her larynx pulling on the chain trying to get away.
She could also have a tumor or polyp on her vocal cords or be dealing with a health issue causing laryngeal paralysis which you can read about here
http://www.peteducation.com/article.cfm?c=2+2096&aid=861
I'd suggest a vet visit for your vet to check her over and determine just what is going on.
She may need to go under anesthesia for the vet to get a good look at her throat to see if this is due to damage or an infection or growth etc.
You might do better with a limited slip on her like this
http://wolfpacks.com/products/collars.html
Hope this helps you!
She might need surgery - the only way to know for sure what exactly the problem is would be an in person vet exam if you can manage that.
You might consider fencing her in or if you can't do that use a tie out with a spring so that she doesn't get full force against her throat here's an example of the type I mean
http://www.redhillgeneralstore.com/A52816.htm#
if you use one of those (heavier type of spring for this sort of dog than the one shown) attached to an overhead cable run that would put less overall pressure on the throat.
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics