Language codes

This guide applies to the branch selected in Current branch. Keys, values, languages, tags and file mappings are independent between branches. See branch navigation and branch permissions.

The language picker searches English names and standard codes. Manual entries use the same server-side validation as search selections.

Supported form

Codes contain a registered language, optionally followed by a script, region and registered variants. Subtags are separated by hyphens.

Code	Meaning
en	English
en-US	English, United States
pt-BR	Portuguese, Brazil
zh-Hant	Chinese, Traditional script
sl-rozaj	Slovenian, Resian variant

Validation uses a versioned local IANA registry snapshot and the pinned Node locale implementation. The running service does not download a catalog from an external provider.

Enter a code

Open the language picker and type into Search languages or enter a code. Select a result, or choose Use entered code. Review the returned English name and canonical code before saving.

Letter case and supported older aliases are normalized. For example, EN-us becomes en-US, and the supported old code iw becomes he. Equivalent forms cannot create multiple records in one branch.

Unsupported forms

This release accepts a defined subset of BCP 47. Private-use codes such as x-team, Unicode extensions such as en-US-u-ca-gregory, extlang forms and grandfathered forms are outside that subset. An unregistered subtag is also rejected.

Do not replace a rejected code with a different language merely to save the form. Choose a supported standard code that represents the intended language.

Existing languages

You cannot add the source as a target or add an equivalent target twice. If the target is inactive, reactivate it.

Region and script subtags do not automatically create fallback links. Configure the relationship explicitly in Fallback chains.