This document describes a language tag for use in cases where it is desired to indicate the language used in an information object. It also defines a Content-language: header, for use in the case where one desires to indicate the language of something that has RFC-822- like headers, like MIME body parts or Web documents, and a new parameter to the Multipart/Alternative type, to aid in the usage of the Content-Language: header.
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All 2-letter tags are interpreted according to ISO standard 639, "Code for the representation of names of languages" [ISO 639].
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All 2-letter codes are interpreted as ISO 3166 alpha-2 country codes denoting the area in which the language is used.
Extrait de [ recommandation Tags for the Identification of Languages]
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