PyMOTW: gettext

The gettext module provides an all-Python implementation compatible
with the GNU gettext library for message translation and catalog
management. The tools available with the Python source distribution
enable you to extract messages from your source, build a message catalog
containing translations, and use that message catalog to print an
appropriate message for the user at runtime.

Message catalogs can be used to provide internationalized interfaces for
your program, showing messages in a language appropriate to the user.
They can also be used for other message customizations, including
“skinning” an interface for different wrappers or partners.

Read more at gettext