True. We expect them to learn our language yet can't learn theirs. And then many call them stubborn or stupid for failing fluency in human language. 

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