W3cubDocs

/HTTP

Content-Language

The Content-Language entity header is used to describe the language(s) intended for the audience, so that it allows a user to differentiate according to the users' own preferred language.

For example, if "Content-Language: de-DE" is set, it says that the document is intended for German language speakers (however, it doesn't indicate the document is written in German. For example, it might be written in English as part of a language course for German speakers).

If no Content-Language is specified, the default is that the content is intended for all language audiences. Multiple language tags are also possible, as well as applying the Content-Language header to various media types and not only to textual documents.

Header type	Entity header
Forbidden header name	no
CORS-safelisted response-header	yes
CORS-safelisted request-header	yes

Syntax

Content-Language: de-DE
Content-Language: en-US
Content-Language: de-DE, en-CA

Directives

language-tag: Multiple language tags are separated by comma. Each language tag is a sequence of one or more case-insensitive subtags, each separated by a hyphen character ("-", %x2D). In most cases, a language tag consists of a primary language subtag that identifies a broad family of related languages (e.g., "en" = English), which is optionally followed by a series of subtags that refine or narrow that language's range (e.g., "en-CA" = the variety of English as communicated in Canada).

Note: Language tags are formaly defined in RFC 5646, which relay on the ISO 639 standard (quite often the ISO 639-1 code list) for language codes to be used.

Examples

Indicating the language a document is written in

The global lang attribute is used on HTML elements to indicate the language of an entire HTML document or parts of it.

<html lang="de">

Do not use this meta element like this for stating a document language:

<!-- /!\ This is bad practice -->
<meta http-equiv="content-language" content="de">

Indicating a target audience for a resource

The Content-Language header is used to specify the intended audience of the page, and can indicate that this is more than one language.

Content-Language: de, en

Specifications

Specification	Title
RFC 7231, section 3.1.3.2: Content-Language	Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

Browser compatibility

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Servo
Content-Language	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)

Feature	Android	Chrome for Android	Edge Mobile	Firefox for Android	IE Mobile	Opera Mobile	Safari Mobile
Content-Language	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)	(Yes)