We follow this custom with racehorses in order to simplify the paperwork for the official age categories in which they compete.
This is why the breeding of racehorses is deliberately scheduled so foals won’t be born late in the calendar year. We wouldn’t want to go down that road with humans.
In Hindi/Urdu a common phrase is “to be of X years [X saal ki honaa]”, even though X is typically counted in current rather than elapsed years. I don’t think they use the ordinal form of numerals (“Xth”) for age.
Actually, people sometimes use a “beginning of the year” convention in casual conversation - “so and so was born in 1960” … “oh, so they’re 52, just like this other person”. Nobody wants to worry about so and so’s actual birthdate at this point, and it seems unwieldy to say “51 or 52” or “52 this year”.
In Viet Nam, they told me they counted a newborn as one year old because of the time in the womb (rounded up I guess), and not because of elapsed years vs. current years. Interestingly, they generally count another year on Tet rather than birthdays, because often people, especially in the countryside, don’t remember when their birthdays are. I joke with them that since I was born six days before Tet, I was two years old before I was a week old.
These different systems are also used in Japan. This leads to some confusion about the age of anime characters - a character who says she’s 16 could (by the Western standard) be 14, 15, or 16 depending on when her birthday is and how she counts years!
You and me neither. I can understand the bit about fractions of days not counting, but surely that is not justification for becoming 21 the day before your 21st birthday!
Even if you were born at 00:00:00 (on the 24 hour clock) on April 27 2012 (or whenever), you still won’t be 21 until April 27 2033. There’s no “fraction of a day” to discount. The system of celebrating your birthday on the actual day inherently weeds out the fractions - if you were born at 23:30 on April 27, you celebrate you birthday from 00:00 on April 27.
The only possible justification I can think of is time zones - when it turns midnight on April 27 in, say, Hawaii (UTC -10), it’s already midnight on April 28 in Kiribati (UTC +14). But I’m sure these laws date from long before the International Date Line was conceived off.
Jim - born 23:59:59, Jan. 1, 2012
John - born 00:00:00, Jan. 2, 2012.
Joan - born 23:59:59, Jan. 2, 2012
Jim turns 1 year old on Jan. 1, 2013. John, who is 1 second younger than Jim, does not turn 1 until the next day. Joan who is only 1 second shy of being a day older that John turns 1 the same day as John. When you start rounding, truncating, flooring, and ceiling, you end up with these things. The method you use to approximate is arbitrary within a wide variety of reasonable options. Just because you’re used to doing it a certain way doesn’t make it the ‘right’ way to do it.
Yes, but it seems to me that this “day before” thing is neither rounding nor truncating nor flooring nor ceiling. It’s fudging.
An a sizable armful who’ve been alive in two millennia.
We occasionally use an expression like “soandso is in his 80th year.” He isn’t 80 years old until his next birthday. I wonder if that isn’t the reason for the Asian calculation - a baby is in his first year as soon as he’s born, not one year old.
When I worked as a secretary for our local jail, there was a woman from the State whose sole job was to check the jailbook ( a record of all persons booked into the jail) for anyone who might have been placed into a regular jail cell who was under 18. She told me a story of some kid who went on a rampage on the eve of his 18th birthday, on the theory he woldn’t be 18 until 2:00 pm on the next day. Wrong! He was charged and tossed into Big Boy Jail so fast it made his head spin!
Do you have an example? Japan dumped the traditional way of counting years in the late 19th century. It can be an issue when dealing with historical figures and sources, but that’s pretty much it. I can’t think of any reason why an anime character would have to introduce themselves using the old system.
I had to explain age to my daughter last month. I told her it was how many birthdays she’d had. “You’re 3 because you’ve had 3 birthdays. Next week you’ll be 4 because it will be your birthday again. And next month your brother will turn 1 because it will be his birthday for the first time.” We’ll discuss her little friend Brianna only having a birthday every fourth year when it comes up.
Dick Clark only had 82 birthdays.
This sounds like the programming language argument about if it’s better to index arrays starting from 0 or 1.
This sounds like the distinction between ordinal and cardinal numbers, with Westerners giving a person’s age as a cardinal number (how many years they’ve been alive) and Easterners giving it as an ordinal number (which year of their life they’re in).
OK, but still, the form they use is very different from either the Spanish or the English forms; the mental concepts are different. Numerals vs ordinals was, frankly, what I cared about the least.
In Spain, someone born in the same year as you is your quinto*, but I have never found an English dictionary which included that meaning, they always translate it by its numeric meaning (“fifth”). Do you guys know an English word with that meaning?
What argument? It’s better to start at 0.
That’s kind of like asking kids what grade they are in at school. But I don’t know an English word that conveys the same thing.
You do if you count them the same way the Church counts how many days Jesus was dead. 
I’m reminded of a lame joke: How many birthdays does the average person have?
Answer: One. All the rest are birthday anniversaries.