extendedLanguageTag
The extended language for the input’s track.
Declaration
var extendedLanguageTag: String? { get set }Discussion
Extended language tags are normally set only when an ISO 639-2/T language code alone is ambiguous. For example, you may use an extended language tag to distinguish media by the regional dialect in use or the writing system employed.
Specify the value as an RFC 4646 language tag, or nil to prevent the writer from writing an extended language tag.