How much money are these researchers spending to establish that dogs have a vocabulary?
We now have the scientific "finding" on Rico the border collie - it asserts that this dog can indeed learn and maybe even draw conclusions. But it suggests that this dog may be an exception, an Einstein dog, even.
This is a case of scientists wasting our time and money. Anyone who has had anything to do with dogs knows that they learn human vocabulary. They also can tell the time, albeit not in the same way as we do. Furthermore, they have added senses beyond ours.
No, they can't talk. But they certainly express themselves.
All the dogs I have owned have not ony learned the spoken commands, but the peripheral language around them. Our present family dog, a 9-year-old doberman, knows the names of all the family members and friends, of all his toys, and of a series of commands, some of them different phrasings of the same command. If asked to go and locate a certain toy, he will get that specific toy. He has a lot of toys. The house sometimes seems to be an obstacle course of his possessions. They all have names - ball, ring, bear, teletubby, rope, chook... He also learned to pee on spoken command. He is not an Einsten dog. He is just a dog from one of the smarter breeds.
We don't need teams of scientists to tell us that dogs learn language.
If they really want to add to the body of knowledge about dogs, let them tell us what dogs think.
That is the mystery.