WPML plugin

Enfold will display the language switcher as soon as two or more languages are set up. Afaik no switcher will be displayed if a page isn’t translated (because it doesn’t make much sense and can irritate the user). You can set up WPML based on the official documentation: http://wpml.org/documentation/getting-started-guide/.

The theme doesn’t require any special configuration. Only one additional step is required – you need to configure the theme options (Enfold menu item on the admin page) for each language – i.e. you can set a different logo, etc. Just select the current language from the language dropdown in the admin panel; the theme name will change – eg to Enfold (DE) if you selected German – and you can configure & save the options for the German website. Then select another language and configure the options for this language, etc.