You want to include locale-specific files in your pages.
Modify include_path once you've determined the appropriate locale, as shown in Example 19-21.
Modifying include_path for localization
In Example 19-21, the $base variable holds the name of the base directory for your included localized files. Files that are not locale-specific go in the global subdirectory of $base, and locale-specific files go in a subdirectory named after their locale (e.g., en_US). Prepending the locale-specific directory and then the global directory to the include path makes them the first two places PHP looks when you include a file. Putting the locale-specific directory first ensures that nonlocalized information is loaded only if localized information isn't available.
This technique is similar to what the img( ) function does in the Recipe 19.7. Here, however, you can take advantage of PHP's include_path feature to have the directory searching happen automatically. For maximum utility, reset include_path as early as possible in your code, preferably at the top of a file loaded via auto_prepend_file on every request.
19.8.4. See Also
Documentation on include_path at http://www.php.net/manual/en/configuration.directives.php#ini.include-path and auto_prepend_file at http://www.php.net/manual/en/configuration.directives.php#ini.auto-prepend-file.