WEBVTT 00:00:06.837 --> 00:00:09.747 In the 1980s, a bonobo named Kanzi 00:00:09.747 --> 00:00:13.637 learned to communicate with humans to an unprecedented extent— 00:00:13.637 --> 00:00:15.587 not through speech or gestures, 00:00:15.587 --> 00:00:20.798 but using a keyboard of abstract symbols representing objects and actions. 00:00:20.798 --> 00:00:25.821 By pointing to several of these in order, he created sequences to make requests, 00:00:25.821 --> 00:00:28.401 answer verbal questions from human researchers, 00:00:28.401 --> 00:00:32.101 and refer to objects that weren’t physically present. NOTE Paragraph 00:00:32.101 --> 00:00:37.041 Kanzi’s exploits ignited immediate controversy over one question: 00:00:37.041 --> 00:00:40.151 had Kanzi learned language? NOTE Paragraph 00:00:40.151 --> 00:00:43.851 What we call language is something more specific than communication. 00:00:43.851 --> 00:00:46.511 Language is about sharing what’s in our minds: 00:00:46.511 --> 00:00:49.871 stories, opinions, questions, the past or future, 00:00:49.871 --> 00:00:52.801 imagined times or places, ideas. 00:00:52.801 --> 00:00:54.811 It is fundamentally open-ended, 00:00:54.811 --> 00:00:59.005 and can be used to say an unlimited number of things. NOTE Paragraph 00:00:59.005 --> 00:01:03.121 Many researchers are convinced that only humans have language, 00:01:03.121 --> 00:01:07.741 that the calls and gestures other species use to communicate are not language. 00:01:07.741 --> 00:01:12.290 Each of these calls and gestures generally corresponds to a specific message, 00:01:12.290 --> 00:01:14.510 for a limited total number of messages 00:01:14.510 --> 00:01:17.870 that aren’t combined into more complex ideas. 00:01:17.870 --> 00:01:21.280 For example, a monkey species might have a specific warning call 00:01:21.280 --> 00:01:24.550 that corresponds to a particular predator, like a snake— 00:01:24.550 --> 00:01:29.459 but with language, there are countless ways to say “watch out for the snake.” 00:01:29.459 --> 00:01:33.404 So far no animal communication seems to have the open-endedness 00:01:33.404 --> 00:01:34.724 of human language. 00:01:34.724 --> 00:01:37.574 We don’t know for sure what’s going on in animals’ heads, 00:01:37.574 --> 00:01:40.053 and it's possible this definition of language, 00:01:40.053 --> 00:01:43.103 or our ways of measuring it, don’t apply to them. 00:01:43.103 --> 00:01:46.593 But as far as we know, only humans have language. 00:01:46.593 --> 00:01:50.593 And while humans speak around 7,000 distinct languages, 00:01:50.593 --> 00:01:53.323 any child can learn any language, 00:01:53.323 --> 00:01:56.813 indicating that the biological machinery underlying language 00:01:56.813 --> 00:01:59.003 is common to all of us. NOTE Paragraph 00:01:59.003 --> 00:02:01.663 So what does language mean for humanity? 00:02:01.663 --> 00:02:05.931 What does it allow us to do, and how did we come to have it? NOTE Paragraph 00:02:05.931 --> 00:02:10.210 Exactly when we acquired this capacity is still an open question. 00:02:10.210 --> 00:02:13.720 Chimps and bonobos are our closest living relatives, 00:02:13.720 --> 00:02:17.870 but the lineage leading to humans split from the other great apes 00:02:17.870 --> 00:02:20.580 more than four million years ago. NOTE Paragraph 00:02:20.580 --> 00:02:24.350 In between, there were many species— all of them now extinct, 00:02:24.350 --> 00:02:29.167 which makes it very difficult to know if they had language or anything like it. 00:02:29.167 --> 00:02:33.277 Great apes give one potential clue to the origins of language, though: 00:02:33.277 --> 00:02:37.277 it may have started as gesture rather than speech. 00:02:37.277 --> 00:02:40.662 Great apes gesture to each other in the wild much more freely 00:02:40.662 --> 00:02:42.622 than they vocalize. NOTE Paragraph 00:02:42.622 --> 00:02:46.072 Language may have begun to take shape during the Pleistocene, 00:02:46.072 --> 00:02:50.314 2 to 3 million years ago, with the emergence of the genus Homo 00:02:50.314 --> 00:02:54.509 that eventually gave rise to our own species, homo sapiens. 00:02:54.509 --> 00:02:59.347 Brain size tripled, and bipedalism freed the hands for communication. 00:02:59.347 --> 00:03:02.497 There may have been a transition from gestural communication 00:03:02.497 --> 00:03:04.060 to gestural language— 00:03:04.060 --> 00:03:07.060 from pointing to objects and pantomiming actions— 00:03:07.060 --> 00:03:10.353 to more efficient, abstract signing. NOTE Paragraph 00:03:10.353 --> 00:03:15.384 The abstraction of gestural communication would have removed the need for visuals, 00:03:15.384 --> 00:03:18.394 setting the stage for a transition to spoken language. 00:03:18.394 --> 00:03:21.484 That transition would have likely come later, though. 00:03:21.484 --> 00:03:25.956 Articulate speech depends on a vocal tract of a particular shape. 00:03:25.956 --> 00:03:30.356 Even our closest ancestors, the Neanderthals and Denisovans, 00:03:30.356 --> 00:03:32.716 had vocal tracts that were not optimal, 00:03:32.716 --> 00:03:34.986 though they likely had some vocal capacity, 00:03:34.986 --> 00:03:36.976 and possibly even language. 00:03:36.976 --> 00:03:40.156 Only in humans is the vocal tract optimal. 00:03:40.156 --> 00:03:45.544 Spoken words free the hands for activities such as tool use and transport. 00:03:45.544 --> 00:03:48.074 So it may have been the emergence of speech, 00:03:48.074 --> 00:03:52.394 not of language itself, that led to the dominance of our species. NOTE Paragraph 00:03:52.394 --> 00:03:57.894 Language is so intimately tied to complex thought, perception, and motor functions 00:03:57.894 --> 00:04:01.998 that it’s difficult to untangle its biological origins. 00:04:01.998 --> 00:04:04.448 Some of the biggest mysteries remain: 00:04:04.448 --> 00:04:08.178 to what extent did language as a capacity shape humanity, 00:04:08.178 --> 00:04:11.338 and to what extent did humanity shape language? 00:04:11.338 --> 00:04:15.638 What came first, the vast number of possible scenarios we can envisage, 00:04:15.638 --> 00:04:17.788 or our ability to share them?