The basic idea is to enable JATS creators to encode structural and metadata components of their document (sections, paragraphs, figures, quotations, tables, etc.) as being the same content, differing only in language. JATS can also encode the relationship between the same content in different languages. (For example: The original author wrote the same content in two or more languages. This section is present twice: one is the original and the second is its translation by a human translator. This section is present twice: one is the original and the second was translated by computer translation.)

In the JATS 1.4, same-content structures in different languages can be flagged as belonging to the same “language group”. JATS defines “language group” as the collection of objects that are the same in content and vary in language. JATS calls alternate language versions of the same content “variants”, and they are collected into a language group by the values of the @lang-group attribute. [[JATSMultilang]] The members of a language group may appear in widely separated places within a document.

Functionality dealing with language groups in an online environment might include: allowing the user to choose whether to see only a particular language version or all the variants, and allowing a user to find an article in a search using a filter specifying the language(s). For example, in an article in both English and Spanish, a user could opt to see only the Spanish, only the English, or both. This would be a function of the display application supported by the JATS markup. [[JATSMultilang]]

How an attribute builds language groups: [[JATSMultilang]]

Once the objects in the language group are identified the creator can provide a variety of information about each of them. It would be surprising if the language of each were not provided, although it is not required. In addition, information about the source of the content and the expected uses may be provided.