Internationalization and localization are two sides of the same coin. Internationalization is the process of developing software so that it can be used in a variety of locations. Localization is the process of modifying an application for use in a specific location. When you internationalize software, you are making it portable; when you localize software, you are actually performing a port.
In the PostgreSQL world, the topics of internationalization and localization are concerned with the following:
Viewing PostgreSQL-. generated messages in the language of your choice
Viewing PostgreSQL-. generated messages in the character set of your choice
Viewing user data in the character set of your choice ...