Lots of dogs know a pretty significant amount of English. Mine knows "potty" and will run to the door, "find mommy" and she'll go find my wife and bark at her, "why did you poop on the floor" and it'll go hide under the bed, "excuse me" and it'll sit somewhere else, etc. If you try to have a conversation with the dog, it'll at least pretend to understand.
I knew someone with a dog that knew the names of each of its ~50 toys and would bring you the correct toy if you asked for it, and knew the difference between "bring me Steven the bear" and "put away Steven the bear."
My cat knows the word "treat." I suspect he knows more but just doesn't care enough about anything else to respond.