When speech-language pathologist Christina Hunger started pressing a paw-sized button that said “outside” every time she took her dog out, Stella began stringing buttons into sentences — the story behind Hunger’s book How Stella Learned to Talk. TheyCanTalk.org, started by cognitive scientist Leo Trottier with Alexis Devine and the AIC Test Pilots group, keeps a free button-teaching curriculum and a research community for anyone attempting the same with their own dog or cat.