The site should be set up with the needed language nodes. Language Copy and the Translation workflow can be used to copy pages, as described at http://dev.day.com/docs/en/cq/current/administering/multi_site_manager.html.
To show the flag of a country whose name is different from the language name, the node needs to have the country code in addition to the language abbreviation. The Language Manager settings in Felix can establish defaults as well.
Example: to show the US flag instead of Great Britain, the node should be en_us; to show the Brazilian flag, the node should be pt_br; to show the Canadian flag, the node should be fr_ca.