Modularizing software allows for easier localization; that is, a properly modularized application requires that fewer files be modified to localize the application. Guidelines for designing modularized software are as follows:
In general, you should modularize your application so that
elements that need to be translated to different languages
are in separate files, and that those files are the only files
that will need changes for localization.
Furthermore, you should have a different set of language-dependent
text files for each locale that are read in at run time using
the internationalization tools available on your system.