Edit to clarify that I used the full declaration and not only the article 1
The way to answer your question is to have a sample of the same long text translated in many languages. The only example I know is the universal declaration of human right, which has 380 reasonably complete translations hosted at http://www.unicode.org/udhr/. Then one just has to count the characters and have the answer.
Caveats of the method
However, the method has several caveats.
1. Variety of the Translations
According to the website, different orthographies of the same language correspond to different translations, which is probably what explains the difference between the two Chinese versions (3737 characters vs 4677). The amplitude of the difference in the two Chinese versions is quite big (20%) for two orthographies which have one character/syllable and encode the same language. It may reflect the stylistic difference of the two translators, and I suppose that this difference can be used as a warning to take all the number below with a big grain of salt. The error bars are likely to be bigger than 20%.
Some of the translation do not contain the preamble, while most of the texts contain it. So it’s not exactly the same text each time. Other differences might exist, since I guess no one can check all the 380 languages.
I’ve come across two identical texts for different languages (Ashéninka Perené and Cashinahua). I guess it’s a technical error, and other errors are probably in the text.
2. Specific nature of the text.
It is a legal text. Poetry, love letters, or historic tales have no reason to have the same succinctness. For example, the translation of article 1 in “Ashéninka, Pichis” seems to turn 2 sentences into 5, with a quote. I can only make sense of this if this article needs to define terms which don’t have exact translation.
3. Definition of a character
I have use the simplest definition of a character : it is a Unicode character in the file, as encoded in the file (below the copyright boilerplate). However, this definition has several problems :
- The files are full of white spaces
- They are not normalized, neither as NFC (é is one character) nor NFD (é would be e+acute accente : 2 character). The upside of this is the presumed use of the more usual form for a language (NFC for Korean, an unnormalized version for Vietnamese)
The definition kept by Unicode has sometimes more to do with the history of digital encoding of the scripts than with the real linguistic status of an entity as a character.
For example Korean is written in Hangul, an alphabet where the 2 or 3 letters (jamos) describing a syllable are placed in a square of the size of a Chinese character. Currently, there are two canonically equivalent ways of encoding a Korean syllable in Unicode : one (NFC) with one character, and one (NFC) with a character for each jamo, that is two or three characters/syllable. All that should of course be invisible to the reader.
An other set of example is the way abugidas are encoded. An abugida is an alphabet where the vowel is essentially a diacritic added to the consonant. So the graphical unit is a syllable, but one can distinguish both the consonant and the vowel in this graphical unit. Some of them, like the Ethiopic Ge'ez, used for Amharic, are encoded with one character/syllable while other, like most (all?) Indic scripts are encoded as a complex script with one character/consonnant and vowel, that is typically two character/syllable. While one could argue that this factor 2 corresponds to a more succinct digital representation of the script in the Unicode standard, it does not to corresponds to anything in term of the script itself.
The most succinct language is Mandarin Chinese, in traditional characters, followed by the same language in simplified characters. With little surprise, in the 10 most succinct languages, one has languages with one syllable per character (Chinese, Yi, Amharic, Korean) and Japanese (which is a very special system). However, a few languages (Waama, Even, Cashinahua ,Beti) written in an alphabetical system (latin and cyrillic) make it into the top 10, while some 1 character/syllable don’t make it (Tigrina, Cree, Vai, etc.) and no abjad (alphabet without the vowels) makes it.
Article 1 in various languages, as an illustration.
Below is the article 1 of this declaration in a few languages sorted by the total number of character used in the declaration. This number given after the language name and counts the number of characters in the full declaration (i.e. the 30 articles, and the preamble when present).
I first give 10 the most succinct languages, then English for reference, and the least succinct language.
Chinese, Mandarin (Traditional) : 3737
Chinese, Mandarin (Simplified) : 4677
Yi, Sichuan : 4910
Waama : 5121
Yiriba na bà sikindo dare bà mɛɛri, da seena yirimma mii bà ta da i nɛki bà tɔɔba.
Even : 5299 (no preamble)
Бэйил бокэтчур омэн хилкич нян урумкэр балдаритно, теми ноҥардук эгдьэн ҥи‐да ачча. Бэйил бөкэтчур мэн долан акагчимур биннэтын.
Ashéninka Perené or Cashinahua : 5576
(The the files are almost identical ! It's probably an error. I guess that the following is in one of the languages, but I don’t know which.)
Yudabu dasibi jabiaskadi akin, xinantidubuki. Javen taea jau jaibunamenunbunven.
Japanese : 5865
Amharic : 6393 (No preamble)
Korean : 6400
(The file is in NFC: 1 character per syllable. A file dormalized in NFD, with 1 character/jamo would be two or three times longer)
제 1 조
모든 인간은 태어날 때부터 자유로우며 그 존엄과 권리에 있어 동등하다. 인간은 천부적으로 이성과 양심을 부여받았으며 서로 형제애의 정신으로 행동하여야 한다.
Beti : 7428
Abiali bod bese, tege ai sesala, bene etie dzia a mis memvende y'enyiñ, dzom dzia etu fili nkóbó, fili ntsogan, fili mboan. Ve abiali te, mod ose ayem dze ene abe, dze ene mbeñ asu e mod mbog antoa ai mfi na enyiñ ewulu mezen mene sosoo.
English : 12322
All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.
Ashéninka, Pichis : 28432
Maaroni atziripayeeni, ovaquera intzimapaaque, eero ocantzi iñaashitacaavaitaityaari iromperanataityaari. Eejatzi oquemitari iroñaaca te apantyaaro amanitashireteri atziri ancanteri: "Te pirjiperote eeroca, iriima irinta iriitaque ñaaperori". Eejatzi oquemitari te oncameethate intzime aparoni atziri antayetashityaarone caari ishinetaacairi pashine irantero. Tema maaroni ayotziro ampampithashirvaayeta, ayotziro tsicarica otzimayetzi cameethatatsiri anteri o tsicarica otzimi caariperotatsiri, irootaque ocovaperotantari iroñaaca entacotavacaayetya anquemitacaantanaquero arentzitavacaatyeeyaami ocaaquiini.