Fact · Languages and accents
BCP 47 says that a region subtag is typically used to indicate variations such as regional dialects or usage, or region-specific spelling conventions.
Checked against its source on October 17, 2026
In the source's own words
“Typically, a region subtag is used to indicate variations such as regional dialects or usage, or region-specific spelling conventions.”
Tags for Identifying Languages (BCP 47, RFC 5646), Addison Phillips and Mark Davis, Internet Engineering Task Force (IETF), 2009, Section 2.2.4 Region Subtag.
Open the original- What it measures
- A language tag such as en-GB combines the language subtag en with the region subtag GB. The standard uses the region to mark differences such as spelling conventions between regions.
- What it does not show
- The standard defines the tag format. It does not say which regions a speech product supports, and it does not say how accurately a locale is recognized.