@documentlanguage ll[_cc]: Set the Document Language ¶The @documentlanguage command declares the current document
locale. Write it on a line by itself, near the beginning of the file.
@documentlanguage ll[_cc]
Include a two-letter ISO 639-2 language code (ll) following
the command name, optionally followed by an underscore and two-letter
ISO 3166 two-letter country code (cc). If you have a
multilingual document, the intent is to be able to use this command
multiple times, to declare each language change. If the command is
not used at all, the default is en_US for US English.
As with GNU Gettext (see Gettext), if the country
code is omitted, the main dialect is assumed where possible. For
example, de is equivalent to de_DE (German as spoken in
Germany).
For Info and other online output, this command changes the translation
of various document strings such as “see” in cross-references
(see Cross-references), “Function” in defuns (see Definition Commands), and so on. Some strings, such as “Node:”, “Next:”,
“Menu:”, etc., are keywords in Info output, so are not translated
there; they are translated in other output formats.
In DocBook output @documentlanguage sets the language for
following sections.
For LaTeX, this command causes code to load the ‘babel’ package
to be output in the preamble, and \selectlanguage to be output.
For TeX, this command causes a file txi-locale.tex to
be read (if it exists). If @documentlanguage argument
contains the optional ‘_cc’ suffix, this is tried first.
For example, with @documentlanguage de_DE, TeX first looks
for txi-de_DE.tex, then txi-de.tex.
Such a txi-* file is intended to redefine the various English words used in TeX output, such as ‘Chapter’, ‘See’, and so on. We are aware that individual words like these cannot always be translated in isolation, and that a very different strategy would be required for ideographic (among other) scripts. Help in improving Texinfo’s language support is welcome.
@documentlanguage also changes TeX’s current hyphenation
patterns, if the TeX program being run has the necessary support
included. This will generally not be the case for tex
itself, but will usually be the case for up-to-date distributions of
the extended TeX programs etex (DVI output) and
pdftex (PDF output). texi2dvi will use the
extended TeXs if they are available (see Format with texi2dvi).
Since the lists of language codes and country codes are updated relatively frequently, we don’t attempt to list them here. The valid language codes are on the official home page for ISO 639, http://www.loc.gov/standards/iso639-2/. The country codes and the official web site for ISO 3166 can be found via https://en.wikipedia.org/wiki/ISO_3166.