ITS Tool allows you to translate your XML documents with PO files, using rules
from the W3C Internationalization Tag Set (ITS) to determine what to translate
and how to separate it into PO file messages.

PO files are the standard translation format for GNU and other Unix-like
systems. They present translatable information as discrete messages, allowing
each message to be translated independently. In contrast to whole-page
translation, translating with a message-based format like PO means you can
easily track changes to the source document down to the paragraph. When new
strings are added or existing strings are modified, you only need to update
the corresponding messages.

ITS Tool is designed to make XML documents translatable through PO files by
applying standard ITS rules, as well as extension rules specific to ITS Tool.
ITS also provides an industry standard way for authors to override translation
information in their documents, such as whether a particular element should be
translated.