"People have been trying to parse how dogs and people communicate with each other for a long time. Obviously they do—but hypothetically the form and content go way beyond sit and stay—and say something broader about language and animal cognition.
Border collies in particular have been central to this research. In the early 2000s a team of researchers at the Max-Planck Institute for Evolutionary Anthropology in Germany heard about a border collie named Rico whose owners said he knew the names of 200 different objects, mostly toys. So the researchers, led by an evolutionary psychologist named Juliane Kaminski, went to see Rico and tested him."