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+.. -*- mode: rst; encoding: utf-8 -*-
+
+============
+Introduction
+============
+
+The functionality Babel provides for internationalization (I18n) and
+localization (L10N) can be separated into two different aspects:
+
+ * tools to build and work with ``gettext`` message catalogs, and
+ * a Python interface to the CLDR (Common Locale Data Repository), providing
+   access to various locale display names, localized number and date
+   formatting, etc.
+
+.. contents:: Contents
+   :depth: 2
+.. sectnum::
+
+
+Message Catalogs
+================
+
+While the Python standard library includes a
+`gettext <http://docs.python.org/lib/module-gettext.html>`_ module that enables
+applications to use message catalogs, it requires developers to build these
+catalogs using GNU tools such as ``xgettext``, ``msgmerge``, and ``msgfmt``.
+And while ``xgettext`` does have support for extracting messages from Python
+files, it does not know how to deal with other kinds of files commonly found
+in Python web-applications, such as templates, nor does it provide an easy
+extensibility mechanism to add such support.
+
+Babel addresses this by providing a framework where various extraction methods
+can be plugged in to a larger message extraction framework, and also removes
+the dependency on the GNU ``gettext`` tools for common tasks, as these aren't
+necessarily available on all platforms. See `Working with Message Catalogs`_
+for details on this aspect of Babel.
+
+.. _`Working with Message Catalogs`: catalogs.html
+
+
+Locale Data
+===========
+
+Furthermore, while the Python standard library does include support for basic
+localization with respect to the formatting of numbers and dates (the
+`locale <http://docs.python.org/lib/module-locale.html>`_ module, among others),
+this support is based on the assumption that there will be only one specific
+locale used per process (at least simultaneously.) Also, it doesn't provide
+access to other kinds of locale data, such as the localized names of countries,
+languages, or time-zones, which are frequently needed in web-based applications.
+
+For these requirements, Babel includes data extracted from the `Common Locale
+Data Repository (CLDR) <http://unicode.org/cldr/>`_, and provides a number of
+convenient methods for accessing and using this data. See `Locale Display
+Names`_ and `Number and Date Formatting`_ for more information on this aspect
+of Babel.
+
+
+.. _`Locale Display Names`: display.html
+.. _`Number and Date Formatting`: formatting.html