ISO 21636-3:2024

Overview

ISO 21636-3:2024 - Language coding: A framework for language varieties - Part 3: Application of the framework provides practical guidance for applying the ISO 21636 conceptual framework to identify and describe language varieties. It complements ISO 639 (language identification) and is applicable to all human languages including sign languages. The document explains how to indicate basic dimensions and sub-dimensions of linguistic variation (e.g., geographical, temporal, social, medium, situation, person, proficiency, communicative functioning) but does not provide codes or individual identifiers.

Key scope points:

• Applies to natural human languages and sign languages.
• Excludes programming languages and non-linguistic symbol systems.
• Focuses on identification and description of language varieties, not on formal technical metadata schemes.
• Structured analogously to ISO/TR 21636-2 and presupposes vocabulary from ISO 21636-1.

Key topics and requirements

• Identification by dimension: Guidance on how to indicate language varieties according to major dimensions of linguistic variation (space, time, social group, medium, situation, person, proficiency, communicative functioning).
• Interoperability focus: Intended to support harmonized metadata for language resources (LRs) to improve exchange, discoverability and reuse.
• No codes included: The standard specifies descriptive requirements and recommendations but does not define registration lists or concrete identifiers; a registration mechanism is expected in future editions.
• Normative references: Builds on ISO 21636-1 (vocabulary) and ISO 15924 (script codes) and aligns with existing metadata best practices (OLAC, DCMI, CMDI).
• Extension potential: Can be used as a basis for extensions to existing tag systems (for example, BCP 47 language tags) or as candidate descriptors for metadata frameworks.

Applications and intended users

Practical uses and beneficiaries:

• Language technology (LT) developers and NLP teams tailoring models for dialects, registers or modalities (spoken, signed, written).
• Libraries, archives and language repositories seeking fine-grained metadata for language resources (LRs) to improve discoverability and long-term preservation.
• Researchers (sociolinguists, corpus linguists, ethnologists) documenting linguistic variation.
• Media, eLearning, eHealth, eGovernment and ICT sectors requiring accurate language variety descriptions for localization, accessibility, and user adaptation.
• Language educators, language trainers and language documentation projects.

Benefits:

• Enables consistent description of dialects, sociolects, historical stages and modality-specific varieties.
• Improves interoperability of metadata across catalogues, archives and language resource infrastructures.

Related standards and resources

• ISO 21636-1: Vocabulary for the framework
• ISO/TR 21636-2: Conceptual descriptions (reference structure)
• ISO 639: Language identification codes
• ISO 15924: Script codes
• OLAC and Dublin Core (DCMI) metadata practices; ISO 15836-1 recognition
• CMDI (Component Metadata Infrastructure) for LR interoperability
• IETF BCP 47 (language tags), potential extension point
• ISO/IEC 11179 (metadata registries) - conceptual alignment

Keywords: ISO 21636-3, language coding, language varieties, linguistic variation, metadata for language resources, BCP 47 extension, OLAC, CMDI, ISO 639, language technology.