AcceptLanguageHeader
Accept-Language is an HTTP header used by a client to announce preferred natural languages for the response. It participates in content negotiation, allowing servers to tailor content to the user’s language and locale when multiple representations are available.
Syntax and tags: The header lists one or more language ranges, defined by the IANA/BCP 47 language
Negotiation and matching: The server compares the accepted language ranges to the language tags of available
Notes: The header is optional; many user agents set it for localization. It coexists with other mechanisms