Actually, the dog we had for 14 years, actually spoke to me and I understood her.

She had 3 distinct barks, the first two I picked up fairly quickly, but the 3rd one took a while.

One bark was she need to go for a walk to do her business. She would pee in our yard, but not poop in our yard. So, when she needed to go for a poop, she would give off one bark sound.

The second was, I need food or water. Sometimes she would spill her bowl of water and needed a refill.

Anytime we came home after being away, she wouldn't bark, but just give off a happy whine that she was glad we returned.

The last one that took me some time to learn, was... somebody came to our house today when nobody was at home.

A neighbor tipped me off about the strange bark she made when a salesman approached our home, but nobody answered. 

Edited to add: Neither my wife nor my kids could understand her, but I sure did.

FWIW