Content-Language
The HTTP Content-Language header indicates the natural language or languages intended for the audience of the enclosed content.
Usage
The Content-Language header signals the intended audience
for a resource, not necessarily the language the
resource is written in. A French-language text excerpt served
to an English-speaking audience carries en as the
content language, because the audience context matters more
than the literal text language.
Servers use this header alongside content negotiation to serve the appropriate language variant. When a client sends an Accept-Language request header listing preferred languages, the server selects the best match and confirms the choice through Content-Language.
Multiple language tags are separated by commas. Each tag follows the BCP 47 format, combining a primary language subtag with optional region and script subtags.
Values
Single language tag
A single BCP 47 tag identifies one language and optionally
a region. Common examples include en, en-US, de-DE,
and zh-Hans-CN.
Multiple language tags
A comma-separated list indicates content intended for speakers of more than one language. The order does not imply priority.
Content-Language: en, fr
Example
A server responds with a page intended for an
Australian-English audience. The language tag en-AU
identifies English as the primary language and Australia as
the regional variant.
Content-Language: en-AU
A bilingual document intended for both German and French audiences lists both language tags.
Content-Language: de, fr
A server performing content negotiation selects a Spanish variant based on the client request. The response confirms the selection.
Accept-Language: es, en;q=0.8
Content-Language: es
SEO and Content-Language
Content-Language (as an HTTP header or HTML meta tag)
is the primary language signal for Bing, which
weights Content-Language more heavily than
hreflang for ranking locale variants. Google relies on algorithmic
language detection and treats Content-Language as a
weak hint. For international sites targeting Bing,
setting Content-Language is more impactful than
hreflang alone.
Takeaway
The Content-Language header describes the intended audience language for a resource, guiding clients and search engines in language identification and content negotiation.