Zombie Throats

Aside from the throat of a human being a good target for a zombie attack the throat of a zombie is also intriguing.

When spotting a zombie it sometimes isn't the site or the smell of them, one can be identified by the sound of them. Zombies have a very noticeable moan or very long yawn that sounds varying from loud and annoying to quiet and inconspicuous.

Why?
Why do zombies make the noise they make? Thinking about the fairly complex breathing system we have and how efficient it is to make breathing quiet you'd think zombies would also have the same system but they seem to make the weird breathing noise.

One of my many theories is that when whatever virus (yes virus) attacks the host it closes off most of the hosts bodily functions that aren't vital to the zombies survival. Thus the throat closes because that much air intake is not vital or needed for the zombies survival. So the throat closes to restrict the air intake. Seeing as there are many different types of viruses that could make a person into a zombie it is very dependent on that variable.

EDIT- Ill continue this section in a little i just want to publish something other than the intro.