7-bit ASCII: English
A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  a  b  c  d  e  b  g  h  i  j  k  l  m  n  o  p  q  r  s  t  u  v  w  x  y  z    (plus 10 numerals, 33 punctuations marks, 33 communication controls)

8-bit ANSI Extended: European
Š  Œ  Ž  š  œ  ž  Ÿ  À  Á  Â  Ã  Ä  Å  Æ  Ç  È  É  Ê  Ë  Ì  Í  Î  Ï  Ð  Ñ  Ò  Ó  Ô  Õ  Ö  Ø  Ù  Ú  Û  Ü  Ý  Þ  ß  à  á  â  ã  ä  å  æ  ç  è  é  ê  ë  ì  í  î  ï  ð  ñ  ò  ó  ô  õ  ö  ø  ù  ú  û  ü  ý  þ  ÿ

ISO-8859-5: Cyrillic
А  Б  В  Г  Д  Е  Ж  З  И  Й  К  Л  М  Н  О  П  Р  С  Т  У  Ф  Х  Ц  Ч  Ш  Щ  Ъ  Ы  Ь  Э  Ю  Я  а  б  в  г  д  е  ж  з  и  й  к  л  м  н  о  п  р  с  т  у  ф  х  ц  ч  ш  щ  ъ  ы  ь  э  ю  я

ISO-8859-7: Greek
Α  Β  Γ  Δ  Ε  Ζ  Η  Θ  Ι  Κ  Λ  Μ  Ν  Ξ  Ο  Π  Ρ  Σ  Τ  Υ  Φ  Χ  Ψ  Ω  α  β  γ  δ  ε  ζ  η  θ  ι  κ  λ  μ  ν  ξ  ο  π  ρ  ς  σ  τ  υ  φ  χ  ψ  ω

Shift-JIS: Japanese
あ  い  う  え  お  か  き  く  け  こ  さ  し  す  せ  そ  た  ち  つ  て  と  な  に  ぬ  ね  の  は  ひ  ふ  へ  ほ  ま  み  む  め  も  ゃ  や  ゅ  ゆ  ょ  よ  ら  り  る  れ  ろ  わ  を  ん  ア  イ  ウ  エ  オ  カ  キ  ク  ケ  コ  サ  シ  ス  セ  ソ  タ  チ  ツ  テ  ト  ナ  ニ  ヌ  ネ  ノ  ハ  ヒ  フ  ヘ  ホ  マ  ミ  ム  メ  モ  ヤ  ユ  ヨ  ラ  リ  ル  レ  ロ  ヮ  ワ  ヲ  ン  (2524 kana and 6355 kanji)

Big5: Chinese
一  乙  丁  七  乃  九  了  二  人  儿  入  八  几  刀  刁  力  匕  十  卜  又  三  下  丈  上  丫  丸  凡  久  么  也  乞  于  亡  兀  刃  勺  千  叉  口  土  士  夕  大  女  子  孑  孓  寸  小  尢  尸  山  川  工  己  已  巳  巾  干  廾  弋  弓  才  丑  丐  不  中  丰  丹  之  尹  予  云  井  互  五  亢  仁  什  仃  仆  仇  仍  今  介  仄  元  允  內  六  兮  公  冗  凶  分  切  刈  勻  勾  勿  化  匹  午  升  卅  卞  厄  友  及  反  壬  天  夫  太  夭  孔  少  尤  尺  屯  巴  幻  廿  弔  引  心  戈  戶  手  扎  支  文  斗  斤  方  日  曰  月  木  欠  止  歹  毋  比  毛  氏  水  火  爪  父  爻  片  牙  牛  犬  王  丙  (4808 common plus 6334 supplemental)

ISO-639-1 two-letter codes

isIcelandic   noNorwegian   svSwedish   fiFinnish   daDanish   etEstonian   lvLatvian   ltLithuanian   gaIrish   glGalician   cyWelsh   nlDutch   deGerman   enEnglish   eoEsperanto   htCreole   frFrench   caCatalan   euBasque   esSpanish   ptPortuguese   itItalian   mtMaltese   laLatin   plPolish   csCzech   skSlovak   huHungarian   slSlovene   sqAlbanian   elGreek   trTurkish   hrCroatian   bsBosnian   srSerbian   mkMacedonian   roRomanian   bgBulgarian   beBelarusian   ukUkrainian   ruRussian   mnMongolian   kaGeorgian   hyArmenian   azAzerbaijani   yiYiddish   heHebrew   faFarsi   urUrdu   arArabic   soSomali   haHausa   igIgbo   swSwahili   afAfrikaans  
neNepali   paPunjabi   hiHindi   guGujarati   mrMarathi   teTelugu   knKannada   taTamil   bnBengali  
zhChinese   koKorean   jaJapanese   thThai   loPhasa Lao   kmKhmer   viVietnamese   msMalay   idIndonesia   jvJavanese   miMaori

ISO-639-2 three-letter codes

hrmHmong   filFilipino   cebCebuno

Bosnianbs-Cyrl  bs-Latn

Serbiansr-Cyrl  sr-Latn

Azerbaijaniaz-Latn  az-Cyrl  az-Arab

Chinese: zh-Hans  zh-Hant

Englishen-Latn

Russianru-Cyrl

Greekel-Grek

Hebrewhe-Hebr

English

Portuguese

RFC 5646 says "region" codes can be omitted when not needed, leaving just ...

en  pt  pt-BR

1. Browser request

            GET / HTTP/1.1
            Host: nuclearfree.earth
            Accept-Language: de,en;q=0.7,en-us;q=0.3
						

2. Server response

            Content-Language: de
            Location: https://de.nuclearfree.earth/
            Status: HTTP/1.1 303 See Other 
						

3. Server redirect request

            GET / HTTP/1.1
            Host: de.nuclearfree.earth
            Accept-Language: de,en;q=0.7,en-us;q=0.3
						

4. Server response

            Content-Language: de
            Location: https://de.nuclearfree.earth/
            Status: HTTP/1.1 200 OK
						

General rule: use the Gregorian calendar

Use digits for the day and year; spell out the month

'Afrikaans', 'Januarie',   'Februarie',   'Maart','April','Mei','Junie','Julie','Augustus','September','Oktober','November','Desember'),
'Cebuano',   'Enero',      'Pebrero',     'Marso','Abril','Mayo','Hunyo','Hulyo','Agosto','Septiyembre','Oktubre','November','December'),
'Greek',     'Iανουάριος', 'Φεβρουάριος', 'Μάρτιος','Aρίλιος','Μάιος','Iούνιος','Iούλιος','Αύγουστος','Σεπτέμβριος','Oκτώβριος','Νοέμβριος','Δεκέμβριος'),
'Galician',  'Xaneiro',    'Febreiro',    'Marzo','Abril','Maio','Xuño','Xullo','Agosto','Setembro','Outubro','Novembro','Decembro'),
'Gujarati',  'જાન્યુઆરી',     'ફેબ્રુઆરી',      'માર્ચ','એપ્રિલ','મે','જૂન','જુલાઇ','ઓગસ્ટ','સપ્ટેમ્બર','ઓકટોબર','નવેમ્બર','ડિસેમ્બર'),
'Hindi',     'जनवरी',       ''फ़रवरी',       'मार्च','अप्रैल','मई','जून','जुलाई','अगस्त','सितम्बर','अक्टूबर','नवम्बर','दिसम्बर'),
'Italian',   'Gennaio',    'Febbraio',     'Marzo','Aprile','Maggio','Giugno','Luglio','Agosto','Settembre','Ottobre','Novembre','Dicembre'),
'Japanese',  '1月',         '2月',          '3月','4月','5月','6月','7月','8月','9月','10月','11月','12月'),
'Georgian',  'იანვარი',     'თებერვალი',    'მარტი','აპრილი','მაისი','ივნისი','ივლისი','აგვისტო','სექტემბერი','ოქტომბერი','ნოემბერი','დეკემბერი'),
'Korean',    '일월',        '이월',          '삼월','사월','오월','6월','7월','8월','9월','10월','11월','12월'),
'Russian',   'Январь',     'февраль',      'март','апрель','май','июнь','июль','август','сентябрь','октябрь','ноябрь','декабрь'),
'Vietnamese','Tháng Một',  'Tháng Hai',    'Tháng Ba','Tháng Tư','Tháng Năm','Tháng Sáu','Tháng Bảy','Tháng Tám','Tháng Chín','Tháng Mười','Tháng Mười Một','Tháng Mười Hai'),
'Chinese',   '一月',        '二月',         '三月','四月','五月','六月','七月','八月','九月','十月','十一月','十二月'),
						

Modern alternatives: Luach, Hijiri, Saka, Yin

ISO 10646 Unicode Standard

IETF RFC 3629 Unicode transformation format

ISO 639 two-letter and three-letter language codes

ISO 15924 four-letter script codes

IETF RFC 5646 language tags

IETF RFC 3282 content language headers

ISO 3166 two-letter country codes

IETF RFC 4343 DNS case insensitivity

IETF RFC 7231 § 5.3.5 content negotiation

W3C Right-to-left text in HTML

W3C Ruby markup and styling

Unicode bidirectional algorithm