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What's the historical origin that makes us write 1.000.000,00 and not 1,000,000.00 (like in English) or 1 000 000,00 (like in French)?

Kyriakos Kyritsis
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  • We in India use comma as thousands separator. Eg. 25,000 (Twentyfive thousand). However, what is important is convenient of use. There need not be any fixed rules. The only problem is it does not convey the proper meaning to others, living in other countries. Vaikom Madhu –  Aug 22 '16 at 11:02

2 Answers2

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Belgium, Denmark, Germany, Italy, Romania, Sweden and most of Europe use the dot as a thousands separator, but the space is adopted as well. Even if it must be said that the International Standard recommends spaces in lieu of dots or commas.

As stated on this wikipedia page, before the invention of printing, a line ( ¯ ) was used over the digits. After printing, the countries/nations chose marks for convenience and according to what others had already chosen to avoid confusion. This means that it basically was an arbitrary decision, no particular reasons were behind it, apparently.

Alenanno
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  • In order to avoid confusion wouldn't it have been better to choose symbols consistently? – mariosangiorgio Nov 19 '13 at 09:26
  • In cursive the apostrophe was taught as the thousands separator in Italian school when I attended, you may want to mention this if it has a more general validity – Sklivvz Nov 19 '13 at 10:07
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    @Sklivvz Is that standard? I'm asking because personally I've never seen it, as far as I remember but well, who knows. :D – Alenanno Nov 19 '13 at 10:32
  • @mariosangiorgio Probably, but I'm not the one that decided. :P – Alenanno Nov 19 '13 at 10:32
  • @Alenanno it was taught as the one and only way to me... not sure if it ports though – Sklivvz Nov 19 '13 at 10:53
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    @Alenanno Can you point to some source clearly stating that Italy uses baseline dots as the thousand separator? – egreg Nov 19 '13 at 11:44
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    FWIW, Windows by default uses the dot as currency thousands separator when you select the Italian regional settings. – Matteo Italia Nov 19 '13 at 13:02
  • @MatteoItalia That at most proves that the programmer uses them. Out of joke: I know that many people use those periods, but it's neither a requirement nor good practice. – egreg Nov 19 '13 at 20:52
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    @egreg: nope, programmers don't use thousands separators and always use dot as decimal separator. I myself prefer to use English versions of my tools because translations are typically way more cryptic than the original, and to avoid becoming mad when looking for error messages on the Internet (also, programmers have no sense of humor :) ) Seriously: I cited Windows because they typically get this regional stuff right, since they have both the manpower and the interest to do so. They surely will have done their research. – Matteo Italia Nov 19 '13 at 21:19
  • @egreg While I was researching for your comment, I realized that the first line was wrong. I fixed it! :) – Alenanno Nov 20 '13 at 00:46
  • If I remember correctly, the dot separator in Italian is usually at the top rather than the bottom... – Tallmaris Nov 22 '13 at 17:00
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You shouldn't, except perhaps when writing by hand.

Separating thousands with periods is cause for ambiguities. When I was young, I was taught to use a raised dot like in 123˙456, not a period; probably different teachers use different conventions. The main reason I see for a dot instead of a thin space is that usually numbers were written on carta a quadretti, so one digit per square.

When printing, use a thin space:

1 000 000

It's just as readable and not confusing. I'd even say it is more readable.

This is recommended by UNI/ISO, as this quote from the book by Roberto Lesina, Il nuovo manuale di stile, Zanichelli 2009 (p. 174):

La spaziatura è il solo metodo universalmente corretto per la separazione fra migliaia. L'uso di altri separatori, quali il punto [...] può portare a grossolani malintesi. [...] Per questi motivi, anche l'ISO sconsiglia l'uso del punto e della virgola come separatori di migliaia», citing «ISO 31-0, Quantities and units, General principles.

I know of no “official” statement that baseline periods are to be used in Italian.

Now, why did this convention enter into common practice? The answer is really easy: typewriters didn't have raised dots. The influence of typewriters on the way we write now has been great: for tens of years, we had only printed, typewritten and handwritten texts, the middle category being prominent in business.

The raised dot had the same fate as ‘È’, that became E', or the digits 0 and 1, that became O (oh) and l (ell), or the guillemets: disparition.

The question might be phrased: why should we use undirected " instead of inverted commas or guillemets? The answer would be the same. By the way, guillemets were hardly found on typewriter keyboard and they are disappearing.

egreg
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    You may argue about readibility, but you cannot say it is wrong, as the dot is the official thousands mark in the Italian language. – nico Nov 18 '13 at 18:01
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    @nico What's the law enforcing this? Can you point to an “official” source for your claim? I can cite ISO/UNI rules that say the contrary. – egreg Nov 18 '13 at 18:05
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    I second @egreg's opinion, and add a quotation from Roberto Lesina, Il nuovo manuale di stile, Zanichelli 2009 (p. 174): «La spaziatura è il solo metodo universalmente corretto per la separazione fra migliaia. L'uso di altri separatori, quali il punto [...] può portare a grossolani malintesi. [...] Per questi motivi, anche l'ISO sconsiglia l'uso del punto e della virgola come separatori di migliaia», citing «ISO 31-0, Quantities and units, General principles». – DaG Nov 18 '13 at 18:06
  • @egreg: OK, I was wrong using the word "official" (although I wouldn't be surprised whether at some point in history some official remark about that had been made). However ISO does not enforce spaces either, they just recommend to use them. Either dots or spaces are what is commonly adopted in Italy and what (used to) be thought in school. PS: note that I do agree with you that dot for decimal and nothing for thousands is the best for readibility. – nico Nov 18 '13 at 18:24
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    @nico Did I say to use a period as the decimal part separator? I don't think so. I said that in elementary school I was taught to write 123˙456 (and 123,456 for decimal numbers). – egreg Nov 18 '13 at 23:04
  • @egreg: sorry I meant dot or comma for decimal (that is what ISO says). Although that also depends on what you're writing. In the scientific world the dot is the decimal separator, no question. – nico Nov 19 '13 at 07:08
  • @nico: «In the scientific world the dot is the decimal separator, no question.» In Italian too? Have you a source? My experience as a mathematician (as well as several reference books) says otherwise. – DaG Nov 19 '13 at 08:47
  • @DaG: pretty much the guidelines of any journal that I know of require dots not commas. But that is mainly because science at an international level is done in English. In my field (biology) even textbooks in Italian use dots, not commas for decimal places. – nico Nov 19 '13 at 09:17
  • @nico: Do you refer to guidelines for journals in Italian? (In English periods are used, guidelines or not, of course.) – DaG Nov 19 '13 at 09:24
  • @DaG: like it or not, at a non-scholastic level science is done in English. I don't know whether mathematicians write a lot in Italian (for reasons I wouldn't quite understand), but definitely English is the language of biology. Anyway, this is not the place to discuss these points. – nico Nov 19 '13 at 10:50
  • @nico: I know very well international, English-language scientific research; I have published several papers in English myself. I was just wondering why you were mentioning English-language guidelines in a site about Italian language. – DaG Nov 19 '13 at 11:02
  • @DaG: because, as said above, the English notation is the general use for science. If I write about science in Italian I use the English notation. That was all – nico Nov 19 '13 at 12:15
  • @nico: Please do, but not everybody does so. – DaG Nov 19 '13 at 12:34