Please make sure that you apply to following naming convention:
- Locale: a combination of language and region that indicates a user language preference, eg.
- Language: the language part of a locale, eg. en. Language identifiers are expected to be ISO 639-1 codes.
- Region: the region part of a locale, eg. US. Region identifiers are expected to be ISO 3166-1 alpha-2 codes.
You’ll find more information on the revel documentation page.