If one want to set up a shop for various countries (e.g. England, Germany, Austria, Switzerland, USA), how could one handle the language? So how could I Zen Cart make to automatically show the language of the land the visitor comes from or / and offer a switcher (e.g. different flags) to be used by a visitor?

And how would one have to manage the different rights of the countries according to the visitor's origin, so how automatically (if at all useful) or / and manually (according to the language a visitor chooses or / and his browser automatically detects) provide the right process?