0:00:07.073,0:00:10.273 Grammatical tense [br]is how languages talk about time 0:00:10.273,0:00:12.734 without explicitly naming time periods 0:00:12.734,0:00:17.014 by, instead, modifying verbs [br]to specify when action occurs. 0:00:17.014,0:00:20.484 So how many different tenses are there[br]in a language like English? 0:00:20.484,0:00:22.685 At first, the answer seems obvious: 0:00:22.685,0:00:23.584 there's past, 0:00:23.584,0:00:24.385 present, 0:00:24.385,0:00:25.805 and future. 0:00:25.805,0:00:28.365 But thanks to something called[br]grammatical aspect, 0:00:28.365,0:00:32.034 each of those time periods [br]actually divides further. 0:00:32.034,0:00:34.144 There are four kinds of aspect. 0:00:34.144,0:00:36.555 In the continuous or progressive aspect, 0:00:36.555,0:00:39.885 the actions are still happening [br]at the time of reference. 0:00:39.885,0:00:43.905 The perfect aspect describes actions[br]that are finished. 0:00:43.905,0:00:46.437 The perfect progressive aspect [br]is a combination, 0:00:46.437,0:00:49.967 describing a completed part [br]of a continuous action. 0:00:49.967,0:00:52.446 And finally, there's the simple aspect, 0:00:52.446,0:00:55.945 the basic form of the past, [br]present, and future tense, 0:00:55.945,0:00:59.936 where an action is not specified[br]as continuous or discrete. 0:00:59.936,0:01:03.616 That's all a little hard to follow,[br]so let's see how it works in action. 0:01:03.616,0:01:06.827 Let's say your friends tell you[br]they went on a secret naval mission 0:01:06.827,0:01:09.567 to collect evidence [br]of a mysterious sea creature. 0:01:09.567,0:01:12.587 The tense sets the overall frame[br]of reference in the past, 0:01:12.587,0:01:15.066 but within that, there are many options. 0:01:15.066,0:01:17.658 Your friends might say a creature[br]attacked their boat, 0:01:17.658,0:01:20.617 that's the past simple,[br]the most general aspect, 0:01:20.617,0:01:23.287 which gives no further clarification. 0:01:23.287,0:01:25.577 They were sleeping when it happened, 0:01:25.577,0:01:29.009 a continuous process [br]underway at that point. 0:01:29.009,0:01:32.387 They might also tell you they had departed[br]from Nantucket 0:01:32.387,0:01:35.338 to describe an action [br]completed even earlier. 0:01:35.338,0:01:38.088 That's an example of the past perfect. 0:01:38.088,0:01:41.198 Or that they had been sailing [br]for three weeks, 0:01:41.198,0:01:44.389 something that was ongoing [br]up until that point. 0:01:44.389,0:01:48.558 In the present, they tell you that [br]they still search for the creature today, 0:01:48.558,0:01:50.840 their present simple activity. 0:01:50.840,0:01:55.708 Perhaps they are preparing for their[br]next mission continuously as they speak. 0:01:55.708,0:02:00.158 And they have built a special [br]submarine for it, a completed achievement. 0:02:00.158,0:02:04.803 Plus, if they have been researching[br]possible sightings of the creature, 0:02:04.803,0:02:08.267 it's something they've been doing [br]for a while and are still doing now 0:02:08.267,0:02:11.469 making it present perfect progressive. 0:02:11.469,0:02:13.722 So what does this next mission hold? 0:02:13.722,0:02:18.138 You know it still hasn't happened[br]because they will depart next week, 0:02:18.138,0:02:19.596 the future simple. 0:02:19.596,0:02:22.730 Your friends will be searching [br]for the elusive creature, 0:02:22.730,0:02:25.899 an extended continuous undertaking. 0:02:25.899,0:02:30.517 They tell you the submarine will have[br]reached uncharted depths a month from now. 0:02:30.517,0:02:31.989 That's a confident prediction 0:02:31.989,0:02:35.719 about what will be achieved [br]by a specific point in the future, 0:02:35.719,0:02:39.059 a point at which they [br]will have been voyaging for three weeks 0:02:39.059,0:02:41.409 in the future perfect progressive. 0:02:41.409,0:02:44.009 The key insight to all these [br]different tenses 0:02:44.009,0:02:47.631 is that each sentence takes place[br]in a specific moment, 0:02:47.631,0:02:50.900 whether it's past, present, or future. 0:02:50.900,0:02:54.159 The point of aspects is that they tell you[br]as of that moment 0:02:54.159,0:02:56.369 the status of the action. 0:02:56.369,0:03:00.059 In total, they give us twelve [br]possibilities in English. 0:03:00.059,0:03:01.940 What about other languages? 0:03:01.940,0:03:03.219 Some, like French, 0:03:03.219,0:03:04.080 Swahili, 0:03:04.080,0:03:07.069 and Russian[br]take a similar approach to English. 0:03:07.069,0:03:09.811 Others describe [br]and divide time differently. 0:03:09.811,0:03:12.979 Some have fewer grammatical tenses,[br]like Japanese, 0:03:12.979,0:03:16.730 which only distinguishes past [br]from non-past, 0:03:16.730,0:03:18.482 Buli and Tukang Basi, 0:03:18.482,0:03:21.742 which only distinguish future [br]from non-future, 0:03:21.742,0:03:26.192 and Mandarin Chinese [br]with no verb tenses at all, only aspect. 0:03:26.192,0:03:31.622 On the other hand, languages like Yagwa[br]split past tense into multiple degrees, 0:03:31.622,0:03:35.602 like whether something happened hours, [br]weeks, or years ago. 0:03:35.602,0:03:39.592 In others, tenses are intertwined[br]with moods that can convey urgency, 0:03:39.592,0:03:40.706 necessity, 0:03:40.706,0:03:42.902 or probability of events. 0:03:42.902,0:03:45.966 This makes translation difficult[br]but not impossible. 0:03:45.966,0:03:50.215 Speakers of most languages without certain[br]tenses can express the same ideas 0:03:50.215,0:03:53.767 with auxiliary words, [br]like would or did, 0:03:53.767,0:03:55.876 or by specifying the time they mean. 0:03:55.876,0:03:58.085 Are the variations [br]from language to language 0:03:58.085,0:04:01.992 just differents ways of describing[br]the same fundamental reality? 0:04:01.992,0:04:06.616 Or do their diverse structures reflect[br]different ways of thinking about the world 0:04:06.616,0:04:08.337 and even time itself? 0:04:08.337,0:04:12.086 And if so, what other ways [br]of conceiving time may be out there?