Vietnamese language and computers
The Vietnamese language is written with a Latin script with diacritics (accent tones) which requires several accommodations when typing on phone or computers.
Telex is the oldest input method devised to encode the Vietnamese language with its tones.
Historically, Vietnamese was also written in chữ Nôm, which is mainly used for ceremonial and traditional purposes in recent times, and remains in the field of historians and philologists.
[3] Unicode has become the most popular form for many of the world's writing systems, due to its great compatibility and software support.
The Middle Vietnamese letter B with flourish (ꞗ) is included in the Latin Extended-D block.
For systems that lack support for Unicode, dozens of 8-bit Vietnamese code pages have been designed.
[8][9] Where ASCII is required, such as when ensuring readability in plain text e-mail, Vietnamese letters are often encoded according to Vietnamese Quoted-Readable (VIQR) or VSCII Mnemonic (VSCII-MNEM),[10] though usage of either variable-width scheme has declined dramatically following the adoption of Unicode on the World Wide Web.
[12] Popular web browsers lack support for specialty Vietnamese encodings, so any webpage that uses these fonts appears as unintelligible mojibake on systems without them installed.
[13] In advertising signage and in cursive handwriting, diacritics often take forms unfamiliar to other Latin alphabets.
Many fonts support a subset of the Latin writing system that omits much of the Vietnamese alphabet.
Like other CJKV writing systems, chữ Nôm is traditionally written vertically, from top to bottom and right to left.
[24] A purely physical Vietnamese keyboard would be impractical, due to the sheer number of letter-diacritic-diacritic combinations in the alphabet e.g. ờ, ị.
Common third-party applications include GoTiengViet, UniKey, VietKey, VPSKeys, WinVNKey, and xvnkb.
By contrast, most IMEs permit the user to insert diacritics at the end of the word: VIEETS in Telex, VIET61 in VNI, or VIET^' in VIQR.
Borrowing a feature common amongst Chinese input methods, some Vietnamese IMEs allow one to skip diacritics altogether and instead, after typing the base letters, the user can select the accented word from a candidate list.
Compound words are never hyphenated in contemporary usage, so spell checkers are limited to checking individual syllables unless a statistical language model is consulted.
