Multiple languages function on a website can be found in a plugin and basically depends on what are you using for your website (manual coding, script, portal, CRM, etc). If you plan to do it manually, you will need to add as the primary language, then use the standard codes for every other language. Also, you need to define this function for all the text and create a script to automatically switch the language using the IP address of the visitor or simply implement a drop-down menu which will change the language to the whole site. To make it easier, you can implement Google or Bing translate tools into your website which make it easier to translate and allow other visitors to switch between different languages.
