Localization Support

Asciidoctor is not restricted to working with English-only content. Asciidoctor can process the full range of the UTF-8 character set. That means you can write your document in any language, save the file with UTF-8 encoding, and expect Asciidoctor to convert the text properly.

Furthermore, you can customize the built-in labels (e.g., “Appendix”) to match the language in which you are writing. The built-in labels that are used in the output generated by Asciidoctor are English by default. These labels can be modified by changing the value of the corresponding attributes.

There are some caveats to know about:

Currently, the official HTML and PDF converters only fully support left-to-right (and top-to-bottom) reading. Support for right-to-left (RTL) is being worked on. See issue #1601 for details. In the interim, you can leverage the DocBook toolchain to get right-to-left support.
Attributes that store dates and times (e.g., docdatetime) are always formatted like 2019-01-04 19:26:06 GMT+0000.
Message (aka logging) strings are always in English.
Asciidoctor does not support the language conf files used by AsciiDoc.py. However, Asciidoctor does provide a translation file that can be used for a similar purpose.

Translating built-in labels

When converting to DocBook, you can rely on the DocBook toolchain to translate (most) built-in labels. To activate this feature, simply set the lang attribute to a valid country code (which defaults to en for English). For example:

$ asciidoctor -a lang=es -b docbook article.adoc

The list of supported languages, as well as additional language considerations for DocBook, are described in DocBook XSL: The Complete Guide.

The lang attribute does not enable automatic translation of built-in labels when converting directly to HTML or PDF. It’s merely a hint to configure the DocBook toolchain. If you’re not using the DocBook toolchain for publishing, you must translate each built-in label yourself. One way is to set the following attributes in the document header or by passing the attributes via the API or CLI:

Attributes that control built-in labels
Attribute	Default English Value	Notes
`appendix-caption`	Appendix
`caution-caption`	Caution
`chapter-label`	Chapter	Applies only when `doctype` is `book`. PDF converter only.
`example-caption`	Example
`figure-caption`	Figure
`important-caption`	Important
`last-update-label`	Last updated
`listing-caption`	not set	By default, listing blocks do not have captions. Specify `listing-caption` to turn on listing block captions.
`manname-title`	NAME	Applies only when `doctype` is `manpage`.
`note-caption`	Note
`preface-title`	not set	Applies only when `doctype` is `book`.
`table-caption`	Table
`tip-caption`	Tip
`toc-title`	Table of Contents
`untitled-label`	Untitled
`version-label`	Version
`warning-caption`	Warning

If you plan to support multiple languages, you’ll want to define the attributes for each language inside a conditional preprocessor directive. For example:

ifeval::["{lang}" == "de"]
:caution-caption: Achtung
...
endif::[]

Of course, you’re probably hoping this has already been done for you. Indeed, it has!

You can find an AsciiDoc file in the Asciidoctor repository that provides translations of these attributes for most major languages. The translations are defined using AsciiDoc attribute entries inside conditional preprocessor blocks, just as suggested above.

To use this file to translate the built-in labels according the value of the lang attribute (just like the DocBook toolchain does), follow these steps:

Download the AsciiDoc file attributes.adoc from the Asciidoctor repository.
Put the file in the folder locale relative to your document.
Add the following line to the header of your AsciiDoc document:
```
include::locale/attributes.adoc[]
```
Set the language using the lang attribute. This attribute must be set before the include directive gets processed. For example:
```
-a lang=es
```

The built-in labels will now be translated automatically based on the value of the lang attribute.

There’s an ongoing discussion about how to make language support even simpler (issue #1129). Input is welcome.

Translation

Asciidoctor (or DocBook) currently does not support translation of content out of the box. There’s a proposal to integrate gettext (discussion), and suggestions are welcome.