When using themes you want to changes some of the translations specifically to the theme while keeping the standard translations for most of the text.
Duplicating the main translation file is a headache for maintainance.
This how to provides a solution.
You would find having such a need in most Yii Projects. Your database needs a specific format to store date fields, while you may want to display it in different formats to the users on forms and other views.
I wanted to keep all the I18N related translations in separate files, so that I would not need to modify the view files or the model files every time I need to update or fix the translations
of application's source language.
Sometimes you want to use exisiting translations for locales, which do not directly match.
An example would be a website targeting Germany (de_de), Austria (de_at) and Switzerland (de_ch, fr_ch, it_ch). Although you may have
exisiting translations for German (de), French (fr) and Italian (it), there are problems using it directly.