go to this JED (Joomla Extensions Directory) or click this _http://extensions.joomla.org/extensions/languages/multi-lingual-content/460?qh=YToxOntpOjA7czo4OiJqb29tZmlzaCI7fQ%3D%3D, you have to install the component and your site will have 2 languange and more, cmiiw
There are MANY plugins that do this for you. http://extensions.joomla.org/search?q=language There ya' go. Many to pick from.
There are loads of third party extensions that you can use as well. Joom!Fish multilingual content manager for example is highly recommend by Joomla pros.
As a former developer of Joom!Fish I consider it as currently the only real solution if you want to run a multilanguage site with single installation. Other options are very expensive.
if you need a perfect multi language site, clone your site once again, install language file according your needs on cloned site, translate the text files with the help for a human translator. This is the best way to translate a site but take some time and effort. else use a google translate plugin, easy but not perfect.