It's difficult to gauge precisely what it is that makes us human, although hordes of anthropologists, linguists, and assorted "postmodernists" have given it the old college try. Many children fervently hope that their pets will go to heaven and many adults are aware that animals feel emotion. But until recently, with the exception of fictional characters like Dr. Doolittle, few people of any stripe believed that animals could understand human language. Lately, however, certain chimps are making chumps of us in that regard. OhioLINK stamps its foot 76 times for the typo Langauge*, considered "high probability" on the Ballard list. (Photo of Kanzi, the "super-intelligent" bonobo chimp, from Discover magazine.)
Postscript: An attentive reader points out that Hugh Lofting's animals did not understand human language; Dr. Doolittle understood their languages.