The HTTP Content-Language header lists the languages and corresponding regions that the content is intended for.
The HTTP Content-Language response header is an indication from the server about the intended audience. This does not specifically refer to the language that the resource is written in, however. For example, an English-speaking audience can be reading a text excerpt that is written in French.
Multiple languages can be specified on a single line, delimited by commas.
By default, resources are assumed to be suitable for people speaking any language.
In this example, the server indicates that the resource is intended for a Australian-English audience.
The Content-Language header describes the language of the intended target audience for the resource.