C, John Pilley's dog, has the vocabulary of a 4-year-old child. Pilley was retired from research linguistics at South Carolina's Wofford College when he adopted C in 2009. His curiosity persisted: How much language can a dog learn? He had a lot of fun finding out. "The goal was to teach C elements of grammar," said Pilley, 85. "But I also wanted her to have a well-rounded life." Through play he has taught her 1,022 words so far. C can identify 1,000 toys and understand simple sentences, for example, "Take the boomerang and put it in the bin." He added that "if we tell her to clean up, she will." Pilley's next ambition is "to teach her to pronounce a word." And here are a few simple tips given by the former professor of Linguistics to train a dog: