This service lets you validate language tags such as de-CH or en-US according to BCP 47 (formerly RFC 4646) and the IANA Language Subtag Registry. The Language Tag Extensions Registry is not used by this service, but this may change in the future.
Separate multiple tags by comma or whitespace. Do not include quality values such as ;q=0.8. As you type, the background color denotes whether all tags are well-formed and valid, any tag is invalid or any tag is not well-formed.
- Input
- en-GB-boont-r-extended-sequence-x-private
- Canonical
- en-GB-boont-r-extended-sequence-x-private
- Input is canonical
- True
- Well-formed
- True
- Valid
- True
- Registry date
- 2025-06-23
- Primary language subtag
-
en – English
- Extended language subtags
- –
- Script subtag
- –
- Region subtag
-
GB – United Kingdom
(as of 2006-03-29 GB no longer includes the Channel Islands and Isle of Man; see GG, JE, IM)
- Variant subtags
-
boont – Boontling
(Jargon embedded in American English)
- Extension subtags
-
-
r
-
extended
-
sequence
- Private subtags
-
private
- Messages
- The 'r-…' extension cannot be validated because the Language Tag Extensions Registry is not yet used by this service.
Feedback
Don't hesitate to send suggestions and comments to Christoph Schneegans (christoph@schneegans.de).