close to the Hanoi variety as spoken sometime after 1600 but before the present. (This is not unlike how English orthography is based on the Chancery Standard of Late Middle English, with many spellings retained even after the Great Vowel Shift.) Computer support The Unicode character set contains all Vietnamese characters and the Vietnamese currency symbol. On systems that do not support Unicode, many 8-bit Vietnamese code pages are available such as Vietnamese Standard Code for Information Interchange (VSCII) or Windows-1258. Where ASCII must be used, Vietnamese letters are often typed using the VIQR convention, though this is largely unnecessary with the increasing ubiquity of Unicode. There are many software tools that help type Roman-script Vietnamese on English keyboards, such as WinVNKey and Unikey on Windows, or MacVNKey on Macintosh, with popular methods of encoding Vietnamese using Telex, VNI or VIQR input methods all included. Telex input method is often set as the default for many devices. Besides third-party software tools, operating systems such as Windows or macOS can also be installed with Vietnamese and Vietnamese keyboard, e.g. Vietnamese Telex in Microsoft Windows. Dates and numbers writing formats Vietnamese speak date in the format "day month year". Each month's name is just the ordinal of that month appended after the word tháng, which means "month". Traditional Vietnamese however assigns other names to some months; these names are mostly used in the lunar calendar and in poetry. When written in the short form, "DD/MM/YYYY" is preferred. Example: English: 28 March 2018 Vietnamese long form: Ngày 28 tháng 3 năm 2018 Vietnamese short form: 28/3/2018 The Vietnamese prefer writing numbers with a comma as the decimal separator in lieu of dots, and either spaces or dots to group the digits. An example is 1 629,15 (one thousand six hundred twenty-nine point fifteen). Because a comma is used as the decimal separator, a semicolon is used to separate two numbers instead. Literature The Tale of Kiều is an epic narrative poem by the celebrated poet Nguyễn Du, (), which is often considered the most significant work of Vietnamese literature. It was originally written in Chữ Nôm (titled ) and is widely taught in Vietnam (in chữ Quốc Ngữ transliteration). Language variation The Vietnamese language has several mutually intelligible regional varieties: Vietnamese has traditionally been divided into three dialect regions: North, Central, and South. Michel Ferlus and Nguyễn Tài Cẩn found that there was