Script (Unicode)

When multiple languages make use of the same script, there are frequently some differences, particularly in diacritics and other marks. For example, Swedish and English both use the Latin script. However, Swedish includes the character å (sometimes called a Swedish O), while English has no such character. Nor does English make use of the diacritic combining ring above for any character. In general, the languages sharing the same scripts share many of the same characters. Despite these peripheral differences in the Swedish and English writing systems, they are said to use the same Latin script. Thus, the Unicode abstraction of scripts is a basic organizing technique. The differences among different alphabets or writing systems remain and are supported through Unicode’s flexible scripts, combining marks and collation algorithms.

Script versus writing system#edit

Writing system is sometimes treated as a synonym for "script". However, it also can be used as the specific concrete writing system supported by a script. For example, the Vietnamese writing system is supported by the Latin script. A writing system may also cover more than one script; for example, the Japanese writing system makes use of the kanji, hiragana and katakana scripts.

Most writing systems can be broadly divided into several categories: logographic, syllabic, alphabetic (or segmental), abugida, abjad and featural; however, all features of any of these may be found in any given writing system in varying proportions, often making it difficult to purely categorize a system. The term complex system is sometimes used to describe those where the admixture makes classification problematic.

Unicode supports all of these types of writing systems through its numerous scripts. Unicode also adds further properties to characters to help differentiate the various characters and the ways they behave within Unicode text-processing algorithms.

Special script property values#edit

In addition to explicit or specific script properties, Unicode uses three special values:^[5]

Common

Unicode can assign a character in the UCS to a single script only. However, many characters—those that are not part of a formal natural-language writing system or are unified across many writing systems—may be used in more than one script (for example, currency signs, symbols, numerals, and punctuation marks). In these cases Unicode defines them as belonging to the "common" script (ISO 15924 code "Zyyy").

Inherited

Many diacritics and non-spacing combining characters may be applied to characters from more than one script. In these cases Unicode assigns them to the "inherited" script (ISO 15924 code Zinh), which means that they have the same script class as the base character with which they combine, and so in different contexts they may be treated as belonging to different scripts. For example, U+0308 ◌̈ COMBINING DIAERESIS may combine either with U+0065 e LATIN SMALL LETTER E to create a Latin ë or with U+0435 е CYRILLIC SMALL LETTER IE for the Cyrillic ё. In the former case, it inherits the Latin script of the base character, whereas in the latter case, it inherits the Cyrillic script of the base character.

Unknown

The value of "unknown" script (ISO 15924 code Zzzz) is given to unassigned, private-use, noncharacter, and surrogate code points.

Unicode provides a general category property for each character. So in addition to belonging to a script every character also has a general category. Typically scripts include letter characters including: uppercase letters, lowercase letters and modifier letters. Some characters are considered titlecase letters for a few precomposed ligatures such as Dz (U+01F2). Such titlecase ligatures are all in the Latin and Greek scripts and are all compatibility characters, and therefore Unicode discourages their use by authors. It is unlikely that new titlecase letters will be added in the future.

Most writing systems do not differentiate between uppercase and lowercase letters. For those scripts all letters are categorized as "other letter" or "modifier letter". Ideographs such as Unihan ideographs are also categorized as "other letters". A few scripts do differentiate between uppercase and lowercase however: Latin, Cyrillic, Greek, Armenian, Georgian, and Deseret. Even for these scripts there are some letters that are neither uppercase nor lowercase.

Scripts can also contain any other general category character such as marks (diacritic and otherwise), numbers (numerals), punctuation, separators (word separators such as spaces), symbols and non-graphical format characters. These are included in a particular script when they are unique to that script. Other such characters are generally unified and included in the punctuation or diacritic blocks. However, the bulk of characters in any script (other than the common and inherited scripts) are letters.

As of version 18.0, Unicode defines 178 script aliases ("property value aliases") for codes in the ISO 15924 list. Unicode assigns the alias "Common" for ISO 15924's Zyyy code for undetermined scripts, "Inherited" for ISO 15924's Zinh code for inherited scripts, and "Unknown" for ISO 15924's Zzzz code for uncoded scripts. There are script codes defined by ISO 15924 that are not used in Unicode, including Zsym (Symbols) and Zmth (Mathematical notation).

The project Missing Scripts—with contributors from the Mainz University of Applied Sciences, the L'Atelier national de recherche typographique (ANRT) in Nancy, and the University of California, Berkeley—has compiled a list of 131 scripts that have not yet been encoded in The Unicode Standard, out of a total of 294 recognized scripts according to the current state of research.^[11]

• Latin script in Unicode
• Unicode characters
• Unicode symbols
• Phonemic and phonetic orthography

1. ^ "Glossary". unicode.org.
2. ^ "Unicode Character Database: Scripts". unicode.org.
3. ^ "Supported Scripts". unicode.org.
4. ^ https://www.unicode.org/roadmaps/ Roadmaps to Unicode
5. ^ "UAX #24: Unicode Script Property". www.unicode.org.
6. ^ a b c d e f g h i "SEI List of Scripts Not Yet Encoded". Unicode Consortium. March 2023. Retrieved 2023-09-25.
7. ^ "Unicode Pipeline § Code Points Provisionally Assigned for Mature Proposals". Unicode Consortium. 2023-09-12. Retrieved 2023-09-25.
8. ^ Michael Everson (1997-09-18). "Proposal to encode Klingon in Plane 1 of ISO/IEC 10646-2". Archived from the original on 2024-02-13.
9. ^ The Unicode Consortium (2001-08-14). "Approved Minutes of the UTC 87 / L2 184 Joint Meeting".
10. ^ "Middle East-II, Ancient Scripts". The Unicode Consortium. Retrieved 2025-09-21.
11. ^ "The World's Writing Systems". www.worldswritingsystems.org. Retrieved 2024-10-04.

• Script Encoding Initiative, A project at UC Berkeley, USA, working to get more scripts included in the Unicode standard.
• The World’s Writing Systems, An overview of all 294 known writing systems, each with a typographic reference glyph and their Unicode status.