. >> meet kanzi and his younger sister panbanisha.the chimpanzee and an endangered species. they're also superstars in the world of science. >> are you happy kanzi? >> reporter: some scientists believe they can understand spoken english and can communicate by pointing and gesturing. >> let's show sue peanuts. >> reporter: dr. sue discovered their capabilities three decades ago and has since then dedicated her life to studying how early and constant exposure impacts language development. to do that, she's created a culture here of the great a trust in des moines, iowa, that's both human and bonobo. she spends nearly 24 hours a day, seven days a week, interacting with the species. >> it is truly a humbling experience, because i have throughout my life been like a skeptic. and for many years, even now, i have underestimated them. show me egg. >> reporter: as kanzi's language grew, so did this. it's called a election gram board. each represents a word, objects like jell-o and verbs, good, bad, tomorrow and yesterday. there are 400 words o