Translations between languages is quite simple in Magento. For an advanced developer, who has already worked with PHP frameworks, it is not a matter to discuss, but for a beginner it may need a few words of explanation. All texts on the page that should be translated, are stored in CSV files, in /app/locale/[language] directory. The [language] part of the path is build of language code, e. g. ‘en_US’.
If you have a look at the files content, you will find that every file structure is the same, one line contains two texts: one in your default language, and one in the destination language. To use the files – also called dictionaries – they must be declared in module’s config file (config.xml). You should put this code directly inside your frontend or admin node of the config file.