ISO 15924 - Frequently Asked Questions (FAQ)

1. What is a script?

   ISO 15924 uses the ISO/IEC 10646 definition of "script": "a set of graphic characters used for the written form of one or more languages". NOTE 1: A script, as opposed to an arbitrary subset of characters, is defined in distinction to other scripts; in general, readers of one script may be unable to read the glyphs of another script easily, even where there is a historic relation between them. NOTE 2: In certain cases, ISO 15924 provides codes which are not subsumed under this definition. Examples: the codes for aliases and the variant codes.

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2. What is the ISO 15924 standard?

   ISO 15924 provides a set of script codes – a four-letter code set and a three-digit code set – for the representation of names of scripts.

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3. How was the ISO 15924 code list developed?

   ISO 15924: Codes for the representation of names of scripts was developed by the ISO TC46/WG3 for use in terminology, lexicography, linguistics, and various computer applications. It was devised to represent most of the major scripts of the world that are found in the world's literature.

   For more information about the development of the ISO 15924 codes, please see:
   www.unicode.org/iso15924/develop.html

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4. Who uses the ISO 15924 codes and why?

   The ISO 15924 codes were originally devised for use by libraries, information services, and publishers to indicate language in the exchange of information, especially in computerized systems. The codes were expected to be widely used in the library community and to be adopted for any application requiring the expression of language in coded form by terminologists and lexicographers. Today (2014) the codes are now widely used by several Unicode standards and BCP 47 and their implementations.

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5. What is the relationship between the Internet BCP 47 (and its predecessors RFC 1766 and RFC 3066) and the ISO 15924 standards?

   The Internet BCP 47 (Tags for Identifying Languages), which replaced RFC 3066 and RFC 1766, describes a script subtag for use in cases where it is desired to indicate the language used in an information object, how to register values for use in this language tag, and a construct for matching such language tags. It is considered an Internet Best Current Practices for the Internet Community and gives guidance for the use of ISO 15924 codes.

   BCP 47 specifies use of the 4-character code from ISO 15924.

   The BCP 47 also specifies the use of optional subtags (e.g. a country code from ISO 3166) and how to register dialect or variant information with IANA when there is no available ISO 15924 code.

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6. Are the script codes intended to be used as abbreviations for the script?

   The script codes in ISO 15924 were developed to serve as a device to identify a script or collection of scripts. They were NOT intended to serve as abbreviations or short forms for scripts, but rather as a code that serves as a device to identify a script name. Some codes in the list consist of letters that are used in the some form of the script name, but this has not been possible in all situations, and, often, one would need to know the English form of the language name to recognize a relationship. There are situations where codes have been selected that diverge from the script name. In using the script codes, systems generally display the script name represented by the code and not the code itself to users. Therefore it becomes irrelevant whether the code is "123", "Wxyz", "Latn" or whatever.

   See section 4.1 of ISO 15924 for criteria for the selection of the language code.

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7. Who is the registration authority for the ISO 15924 standard?

   The Registration Authority for the ISO 15924 codes is:

   The Unicode Consortium
   Box 391476
   Mountain View, CA 94039-1476
   U.S.A.
   E-mail: iso15924@unicode.org

   The registrar for the ISO 15924 codes is:

   Evertype
   Cnoc Sceichín
   Leac an Anfa
   Cathair na Mart
   Co. Mhaigh Eo
   Éire/Ireland
   

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8. What is the function of the registration authority for the ISO 15924 standard?

   The registration authority for the ISO 15924 standards receives and reviews request applications for both new script codes and for changing existing ones according to criteria indicated in the standards.

   The registration authority maintains accurate lists of information associated with registered script codes.

   It also processes and distributes updates of the codes on a regular basis.

   For more information about the registration authorities' duties, please see Annex A of ISO 15924.

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9. What is the Joint Advisory Committee (JAC) for the ISO 15924 standard?

   The Joint Advisory Committee ISO 15924/RA-JAC was established to advise the ISO 15924 registrar and guide coding rule applications (as laid down in the ISO 15924 documentation). It consists of the registrar, a representative of the ISO 639-2/RA, a representative of ISO TC37, a representative of ISO TC467, and two a representatives of ISO/IEC JTC1/SC2. The JAC considers applications for new script codes and votes on whether they will be included.

   More information about the Joint Advisory Committee and its activities can be found at: unicode.org/iso15924/iso15924jac.html.

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10. Are there any electronic discussion lists for the ISO 15924 script codes?

    For general discussion about the ISO 15924 script codes, please write to: unicode@unicode.org.

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11. How does one request new ISO 15924 script codes?

    To request new codes in the ISO 15924 standards, please fill out the online form at: unicode.org/iso15924/iso15924form.html.

    Before submitting your requests, please review the criteria used to define new codes. Appropriate documentation must be provided with the request.

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12. What are the criteria used to define new ISO 15924 language codes?
    

    Requests for additions, deletions, and changes of codes shall be supported by a justification. When ISO 15924/RA consults ISO 15924/RA-JAC about the proposed inclusion, deletion or change, and suggests a code, ISO 15924/RA-JAC is obliged to respond within one month. NOTE: In general, script codes shall be added to ISO 15924

    1. when the script has been coded in ISO/IEC 10646, and
    2. when the script is agreed, by experts in ISO 15924/RA-JAC to be unique and a candidate for encoding in the UCS.

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13. Are separate script codes defined for variants of scripts?

    Yes. Certain typographic variants have been defined, such as the Blackletter (Latf) and Gaelic (Latg) variants of Latin (Latn); the Old Church Slavonic (Cyrs) variant of Cyrillic (Cyrl); Simplified (Hans) and Traditional (Hant) variants of Han ideographs (Hani); Estrangelo (Syre), Western (Syrj), and Eastern (Syrn) variants of Syriac (Syrc); and the Nastaliq (Aran) variant of Arabic (Arab).

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14. What are script code aliases?

    Script code aliases are collective codes which encompass two or more script codes. Examples are: Hrkt "Japanese syllabaries (alias for Hiragana + Katakana)"; Jpan "Japanese (alias for Han + Hiragana + Katakana)"; and Kore "Korean (alias for Hangul + Han)".

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15. What is the timeline used for approving new ISO 15924 script codes?

    After a request for a new, deleted, or changed code is submitted, the registration authority determines whether or not the request meets the relevant criteria.

    The registration authority then informs the requester of the process generally within two weeks of the submission. If the request meets the criteria, the registration authority determines an appropriate code and consults the ISO 15924/JAC. If the first vote is not unanimous, a second round of voting is conducted.

    The original requester will be informed of the JAC decision in six weeks to two months from submission of the original request.

    Results of the JAC decisions will be publicized in a change notice available on the Web.

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16. Can ISO 15924 script codes be changed after they had initially been created?

    ISO 15924 script codes are usually not changed in order to ensure continuity and stability of online retrieval from large databases built over many years. However, when language names associated with codes have been changed, variant forms of a language name may be included in the entry, indicated within parentheses in the code lists.

    Obsolete codes are generally not reassigned when they have been changed or discontinued.

    A list of codes that have been changed or added to the lists are located at: www.unicode.org/iso15924/codechanges.html.

    To request a change to the name of an already defined language name, please see: www.unicode.org/iso15924/iso15924chform.html.

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17. Are the ISO 15924 codes case sensitive?

    ISO 15924 recommends use of the script codes with an initial capital letter followed by three small letters, but they should be considered case-insensitive and are unique codes regardless of case.

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18. How does one indicate the script variation used in a particular country?

    The ISO 15924 standards (and BCP 47) allow for combining the script code with a language code and/or with a country code from ISO 3166 to denote the area in which a script used associated with a language. For instance, Azeri as written in Azerbaijan or in Iran may be indicated with the following:

    az-Latn or az-AZ-Latn
    az-Arab or az-IR-Arab

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19. How does one make distinctions between traditional and simplified Chinese characters and using the ISO 15924 script codes?

    The differences between traditional and simplified Chinese characters can be represented using the ISO 15924 codes "Hant" and "Hans" respectively.

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20. How does one indicate undetermined scripts using the ISO 15924 script codes?

    A number of codes are available in the ISO 15924 list for special purposes:

    Zxxx (Code for unwritten documents) Zyyy (Code for undetermined script) Zzzz (Code for uncoded script)

    This code is used if the script associated with an item cannot be determined or specified.

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21. Is there a mechanism for using locally defined codes?

    If a user wishes to use locally defined codes for scripts not covered by ISO 15924, codes Qaaa through Qabx are reserved for local use. The value of these codes can only be determined by agreement by sender and receiver.

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