zxx

zxx is the ISO 639-3 code for No linguistic content. It is a special code used to identify content that does not contain any linguistic material, such as text in a natural or constructed language or spoken language.

Purpose and usage: The code is used in metadata and language tagging to indicate that a resource has no language content. It is not a language; rather, it marks the absence of language data. It is commonly employed in library catalogs, digital archives, content management systems, and natural language processing workflows to avoid mislabeling content as a language.

Relationship to other codes: zxx is one of several special codes in the ISO 639 family. It is recognized in the IETF’s BCP 47 language tag system as a tag that signals no linguistic content. It is distinct from und (undetermined language), which signals that the language cannot be determined, but may still be language content.

Examples: materials that would be tagged zxx include diagrams, mathematical notations, charts, graphs, logos, musical notation without lyrics, or data tables that contain no text. In such cases, there is no language to identify.

See also: ISO 639-3, BCP 47, content-language.