Korean language and computers

In RFC 1557, a method known as ISO-2022-KR for seven-bit encoding of Korean characters in email was described. Where eight bits are allowed, EUC-KR encoding is preferred. These two encodings combine US-ASCII (ISO 646) with the Korean standard KS X 1001:1992[1] (previously named KS C 5601:1987). Another character set, KPS 9566 (similar to KS X 1001), is used in North Korea.

The international Unicode standard contains special characters for the Korean language in the hangul phonetic system. Unicode supports two methods. The method used by Microsoft Windows is to have each of the 11,172 syllable combinations as code and a preformed font character. The other method encodes letters (jamos) and lets the software combine them correctly. The Windows method requires more font memory but allows better shapes, since it is complicated to create stylistically correct combinations (preferable for documents).

Another possibility is stacking a sequence of medial(s) (jungseong) and a sequence of final(s) (jongseong) or a Middle Korean pitch mark (if needed) on top of the sequence of initial(s) (choseong) if the font has medial and final jamos with zero-width spacing inserted to the left of the cursor or caret, thus appearing in the right place below (or to the right of) the initial. If a syllable has a horizontal medial (ㅗ, ㅛ, ㅜ, ㅠ or ㅡ), the initial will probably appear further left in a complete syllable than in preformed syllables due to the space that must be reserved for a vertical medial, making aesthetically poor what may be the only way to display Middle Korean hangul text without resorting to images, romanization, replacement of obsolete jamo or non-standard encodings. However, most current fonts do not support this.

The Unicode standard also has attempted to create a unified CJK character set which can represent Chinese (Hanzi) and the Japanese (Kanji) and Korean (Hanja) derivatives of this script through Han unification, which does not discriminate by language or region in rendering Chinese characters if the typographic traditions have not resulted in major differences in what a character looks like. Han unification has been criticized.

South Korean Dubeolsik typing example

On a Korean computer keyboard, text is typically entered by pressing a key for the appropriate jamo; the operating system creates each composite character on the fly. Depending on the Input method editor and keyboard layout, double consonants can be entered by holding the shift button. When all jamo making up a syllabic block have been entered, the user may initiate a conversion to hanja (or other special characters) using a keyboard shortcut or interface button; South Korean keyboards have a key for this. Subsequent semi-automated hanja conversion is supported in varying degrees by word processors.

When using a keyboard with another language, most operating systems require the user to type with an original Korean keyboard layout; the most common is Dubeolsik. In other languages, such as Japanese, text can be entered on non-native keyboards with romanization.

Operating systems such as Linux allow engine/hangul/hangul-keyboard='ro, resulting in a romaja keyboard; typing "seonggye" results in 성계.[2] In this configuration, ㄲ is obtained by "gg" rather than ⇧ Shift+G. This allows keying "jasanGun" to obtain 자산군, instead of keying "jasangun" (which would provide 자상운).

Some Korean fonts do not include hanja, and word processors do not allow a user to specify which font to use as a fallback for any hanja in a text; each hanja sequence must be manually formatted for a desired font.

Vertical text is supported poorly (or not at all) by HTML and most word processors. This is not an issue for modern Korean, which is usually written horizontally; until the second half of the 20th century, however, Korean was often written vertically. Fifteenth-century texts written in hangul had pitch marks to the left of syllables which are included in Unicode, although current fonts do not support them.

Programs designed for Korean language-related use include:

• Language recognition
  • A North Korean speech recognition program is said to recognize 100,000 words, with a success rate of over 90 percent.[9]
  • Mongnan (목란; Korea Computer Center,[10] North Korea) – Optical character recognition software, with a reported success rate of 99 percent for printed text and 95 percent for handwriting recognition.[9]
• Input method editors
  • Tan'gun (단군; Pyongyang Information Center, North Korea) – Allows hangul on English versions of Windows.[10]
  • Nalgaeset Hangul Input Method Editor (날개셋 한글 입력기); Kim Yongmook, South Korea) – A hangul input method developed for the 3(se)-beolsik Windows keyboard layout
  • Nabi (나비), ami (아미; South Korea) – Permits hangul on Linux
  • m17n – Permits revised romanization for hangul input on Unix
  • SCIM and IBus – Permits hangul and hanja input on POSIX operating systems (including Linux and BSD)
• Word processors – The following programs include domestic hangul fonts, non-hangul fonts and a hangul-hanja conversion utility.
  • Hangul (Hancom, South Korea)
  • Changdok (창덕; PIC,[10] North Korea) – MS-DOS program developed in April 1990; a Windows version was developed in 1996.[11] It has a personality-cult feature in which pressing Ctrl+I or Ctrl+J produces titles praising Kim Il Sung and Kim Jong Il, respectively.[12]

Hangul jamo characters in Unicode

Unicode hangul compatibility jamo block

Hangul letters are detailed in several parts of Unicode:

• Hangul Syllables (AC00–D7A3)
• Hangul Jamo (1100–11FF)
• Hangul Compatibility Jamo (3130–318F)
• Hangul Jamo Extended-A (A960–A97F)
• Hangul Jamo Extended-B (D7B0–D7FF)

mod hangul {
    const INITIAL_JAMO: [char; 19] = [
        'ㄱ', 'ㄲ', 'ㄴ', 'ㄷ', 
        'ㄸ', 'ㄹ', 'ㅁ', 'ㅂ', 
        'ㅃ', 'ㅅ', 'ㅆ', 'ㅇ', 
        'ㅈ', 'ㅉ', 'ㅊ', 'ㅋ', 
        'ㅌ', 'ㅍ', 'ㅎ', 
    ];
   
    const VOWEL_JAMO: [char; 21] = [
        'ㅏ', 'ㅐ', 'ㅑ', 'ㅒ',
        'ㅓ', 'ㅔ', 'ㅕ', 'ㅖ', 
        'ㅗ', 'ㅘ', 'ㅙ', 'ㅚ', 
        'ㅛ', 'ㅜ', 'ㅝ', 'ㅞ', 
        'ㅟ', 'ㅠ', 'ㅡ', 'ㅢ', 
        'ㅣ', 
    ];
   
    const FINAL_JAMO: [Option<char>; 28] = [
        None,       Some('ㄱ'), Some('ㄲ'), Some('ㄳ'),
        Some('ㄴ'), Some('ㄵ'), Some('ㄶ'), Some('ㄷ'),
        Some('ㄹ'), Some('ㄺ'), Some('ㄻ'), Some('ㄼ'), 
        Some('ㄽ'), Some('ㄾ'), Some('ㄿ'), Some('ㅀ'), 
        Some('ㅁ'), Some('ㅂ'), Some('ㅄ'), Some('ㅅ'), 
        Some('ㅆ'), Some('ㅇ'), Some('ㅈ'), Some('ㅊ'), 
        Some('ㅋ'), Some('ㅌ'), Some('ㅍ'), Some('ㅎ'), 
    ];
   
    const GA_LOCATION: u32 = '가' as u32; // = 44_032
   
    pub fn from_jamo(initial: char, medial: char, last: Option<char>) -> Option<char> {
        if !(
            self::INITIAL_JAMO.contains(&initial)
            && self::VOWEL_JAMO.contains(&medial)
            && self::FINAL_JAMO.contains(&last)
        ) {
            return None;
        }
        char::from_u32(
            self::GA_LOCATION
            + 588 * (INITIAL_JAMO.iter().position(|&c| c == initial)? as u32)
            + 28 * (VOWEL_JAMO.iter().position(|&c| c == medial)? as u32)
            + FINAL_JAMO.iter().position(|&c| c == last)? as u32
        )
    }
}

• Japanese language and computers
• Vietnamese language and computers
• List of CJK fonts
• Chinese input methods for computers
• McCune–Reischauer
• Yale romanization of Korean
• Revised Romanization of Korean
• New Korean Orthography

• Online Korean Virtual Keyboard
• InputKing Online Input System, an online tool for typing Korean
• "Jamo in Unicode" (PDF). (186 KB)
• "Hangul syllables" (PDF). (3.86 MB)
• Hoffmann, Frank. "Korean Studies: Unicode Converter". koreanstudies.com., an online tool for converting Korean text into various coding formats and vice versa