Multilanguage - i18n Drupal module supports translation for nodes, taxonomies, url alias, meta tags, menus and blocks. Set up the site default languages and then for each piece of content add the relative translation.
If you cannot find a module that does exactly what you need then need to write a custom module. First try to find the same functionality in some existing contributed module. Sometimes it is wise to alter or extend an existing module rather then rewriting the functionality from scratch.