Extended Language Subtag
An extended language subtag (`yue` after `zh`), always preceded by the primary language its prefix names. Every extlang is also registered as a primary language, which is its preferred form.
- Subclass Of
Subtag
An extended language subtag (`yue` after `zh`), always preceded by the primary language its prefix names. Every extlang is also registered as a primary language, which is its preferred form.