The language of the cited material can be identified using the @hreflang attribute, which names the language of the document being cited.

Using @hreflang is best practice for naming the language of the cited material. Some publishers insert a phrase in the text to indicate the language of the cited material (for example, “In Japanese”) if they want that information displayed as part of the citation. Such a phrase might also be captured as a <comment> (<comment>In Japanese<comment>) with a @content-type attribute indicating that this is language information (“original language” or similar). This textual display can still be tagged, but the @hreflang attribute is machine processable and should take precedence.