Our world tells time in a variety of ways. It has for a long time. How many hours are in a day? Which direction is clockwise? Do days just touch or can they... overlap? The way you answer those depends on your culture and your language. Zanzibar, Tanzania. The tallest building when you get off the ferry in Stone Town is a famous local landmark called the House of Wonders. On the top there's a clock that might throw off your sense of time. At noon when the sun is directly overhead, its hands read 6 o'clock. At 9am it actually says 3:00! Hm, strange. But you manage to house your wonders and go enjoy tea with a local friend. (Chai time!) You notice her watch and ask for the time. She glances down. You're relieved to see her hands read the same time as yours, 10am. But without stopping to think she nods her head back up to you and says, "4 o'clock." What's going on here? Well a hint: you're near the equator, where the sun rises around the same time every morning, 6 in the local time zone. Everyone's up and starting their day at seven. With such a reliable natural standard timekeeper, that winds up being 1 o'clock Swahili Time. Even though your friend sets her watch "normally", like other Swahili speakers, ask her what time it is and she mentally winds back the hour hand. Watch says one thing, person says another. Here you're surrounded by clocks that read standard time and people who adjust it to Swahili time. Do not get disoriented. This is normal. Like people around the world, their days are repeating cycles. Swahili Time just shifts when the cycle starts. Or maybe you're the shifty one? Well, Swahili time may rotate that circle , but it still splits it into two rounds of 12 hours, with each hour striking twice per day. Surely you're aware of one alternative to this, the 24 hour clock, each hour once per day. But have you taken a tour of Italy and seen all the beautiful campanili? I haven't. If you have, did you find any unusual medieval clocks? I hear there remain some six hour clocks that still tick on like this one. But you don't have to take a trip to the past. Go to Thailand, and you'll meet six hour time tellers there, too. In the Thai way of keeping time, you count the hours from one to six four times a day. So even a standard 24 hour day around the world might be one round of 24 hours, two rounds of twelve, or four rounds of six hours. And that's assuming we're using the new kind of hours... Inside an enormous shopping mall in Dubai there's a huge mechanical elephant clock, a replica of a contraption invented over eight hundred years ago by al-Jazari. Want to know one of the biggest hurdles this clock had to overcome? The way hours shrink and grow. An hour isn't always an hour long. Since ancient times many people have counted hours of daylight. This Egyptian sundial divides sunlight, from sunrise to sunset, into twelve segments. But Egypt like most of the world - and unlike Zanzibar - gets much more light in summer and much less in winter, so the hours on this sundial expand and contract, breathing with the seasons. Technically called "temporal hours" now, they were once considered the true hours versus today's standard "equal hours". Go to Greece and say the word "water thief": klepsydra. Nowadays people will think you mean this, an hourglass. Once though, long ago, it meant this, a water clock. In ancient and medieval times, inventors tinkered tirelessly with these devices, eventually leading to al-Jazari's sophisticated clocks that could keep up with these changing temporal hours. A sidenote I find interesting at this point. In many languages the words for day and day, daylight hours, have different roots. In Swahili, siku versus mchana. In Chinese, two different characters (日 vs 昼). In English, however, day is its own hyperonym! The first Chinese character there is for one full day-night cycle. Traditionally, that was counted in twelve shí, sometimes translated "double hours". So only twelve hours total in a day, and since now we know the fancy term I can say equal hours! But instead of subdividing these hours into minutes, a separate decimal system ran concurrently, splitting the day into hundredths, a hundred kè per day. Then you could cut those into smaller fēn. (Something like that would happen later in the French Revolution.) All three of these words continue to be used today, fitted onto more modern units: twenty four hours, each with four quarter hours and sixty minutes. Subtract one of those double hours and you're reckoning time the old Nāhua way. They divided the daylight day into four parts and the night into seven. They also have a different understanding of the word clockwise. So do this. Face north. Point to the sun, following it from east to west. Counterclockwise. See, circles in this part of the world cycle the other way, like on the famous sunstone unearthed from the streets of Mexico City, symbols run this direction. Now off to northern India, where for ages the day has been ritually divided into eight pahar. These determine the ceremonial and musical theme of the moment, but they're also practical, which you can still see in the Hindustani word for "afternoon". Break it down, it means "two pahar". There are actually many, many smaller and larger units of time. Take the muhūrt, of which there are thirty in a day. Divisible all the way down to fractions of microseconds. You know who else has 30 hour days? Kind of. In Japan, timekeeping has ditched the unequal hours that once characterized Japanese clocks, which count backwards for six temporal hours twice a day. Well, there is this one watchmaker who's crafted a temporal hour watch, but otherwise, Japan fully embraces the 12 and 24 hour clock. And they found a way to top it. (Apply break time limit!) Late night events can stretch to 25 o'clock, 29 o'clock, all the way up to 30. Maybe you feel like if you're up past midnight, it's not tomorrow yet. Not really, I mean, you haven't even gone to bed. The 30 hour clock taps into that sentiment, with the interesting result that the last six hours of the day overlap with what will have been the technical start of your 24 hour day when you wake up tomorrow. To close this out, let's circle back once more to Africa, but a very different place. In Ilé-Ifẹ̀ I'm told there's an old sundial with a circle divided into sixteen segments. But even though the Yorùbá language natively has plenty of numerals up into the millions, you won't catch this farmer rigidly using the numbers one to sixteen to talk about time. Instead he knows the names of birds that routinely cry out at the same moment every day. See in many languages, the time you tell isn't merely a number. The sun, moon, beasts and sequences of human events help keep natural time. Thanks for getting wound up about linguistic clocks with me. Thanks to patrons for supporting this, I hope you enjoy the background sketches, seeing your names in the outro and the other rewards I enjoyed preparing. And thank you for sticking around for language.