Example image of eyePlorer eyePlorer map for 'IETF language tag': Best Current Practice Internet Engineering Task Force IETF Working Group ISO 639 ISO 639-3 ISO 639-5 Capital letter Case sensitivity Letter case Lower case ISO 15924 ISO 3166-1 alpha-2 UN M.49 Internet Assigned Numbers Authority Canadian English English language Locale International Organization for Standardization ISO 3166 Min Nan Hakka Sign language Ethnologue SIL International Yiddish language Unicode Universal Character Set ISO, SIL, and BCP language codes for constructed languages Oxford spelling List of Wikipedias ISO 639-1 Unicode control characters Oddmuse Michael Everson Traditional Chinese characters Meta element EPUB Portable Network Graphics Ukrainian alphabet American and British English spelling differences Simplified Chinese characters Belarusian language Brazilian Portuguese