In HTML and XML documents a language tag is used to indicate the language of content. A language tag is composed of one or more subtags separated by hyphens. Subtags can be of various types. Language tag syntax is defined by the IETF’s BCP 47.
In HTML and XML documents a language tag is used to indicate the language of content. A language tag is composed of one or more subtags separated by hyphens. Subtags can be of various types. Language tag syntax is defined by the IETF’s BCP 47.
Registry of all valid language tags:
https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry