Overview
ISO 24229:2022 - "Information and documentation - Codes for written language conversion systems" defines principles and a registry model for assigning codes that identify written language conversion systems (including transliteration, transcription and romanization). The standard specifies how to construct machine-readable conversion-system identifiers and how to maintain a registry of authorities, codes and attributes to support consistent exchange of conversion metadata across applications.
Key Topics and Requirements
- Code structure: A conversion system code consists of four segments - titular, source spelling system, target spelling system, and identifying segment. Segments are separated by a single colon (:) and elements within segments by a single hyphen (-).
- Character rules: Code elements use limited Unicode ranges: digits 0–9 and Latin letters (A–Z, a–z). Other characters should be omitted or substituted; a hyphen within an element is accepted.
- Titular segment / authority: The titular segment references the conversion system authority (ISO 24229/RA maintains the authority list). If no authority is identifiable, a country code (ISO 3166-1) or “Var” (varia) is used.
- Governance: Procedures cover registration, requirements for new codes, deprecation, user-assigned codes, capitalization rules and abbreviated forms.
- Data model & attributes: A common data model defines attributes for authorities and conversion systems. The model reuses existing ISO code elements (ISO 15924 script codes, ISO 639 language codes, ISO 3166 country codes, ISO 8601 dates) to ensure interoperable metadata.
- Authority identifiers: Principles for constructing authority identifiers and competency criteria for authorities are specified to ensure reliable registry administration.
Applications and Who Uses It
ISO 24229:2022 is practical for any system that must express which written-language conversion method is applied:
- Libraries, archives and bibliographic services for cataloguing names and titles across scripts.
- Lexicographers and terminologists documenting transliteration standards.
- Publishers and editors needing consistent romanization/transliteration metadata.
- NLP, machine translation and speech systems for reverse transliteration, machine pronunciation and conversion workflows.
- Data exchange & metadata standards (catalogs, authority files, bibliographic records, APIs) that require unambiguous, coded identification of conversion rules.
Using standardized conversion-system codes improves interoperability, reproducibility of conversions, and automated processing across multilingual information systems.
Related Standards
Keywords: ISO 24229:2022, written language conversion, conversion system code, transliteration, romanization, transcription, script conversion, ISO 15924, ISO 639, registry, metadata.