Change Language in SharePoint 2013

Prerequisites : 

You have to install SharePoint Language Pack before you use this feature (ex: French, Arabic)

we have two option to change language in SharePoint

1. Via Browser Preferences
2. My Site - Language Selection

Browser Preferences

• First of all navigate to the site collection settings
• Site Collection Administration - > Language Settings.

• Select the language you want to enable in site

•  Navigate to Internet Explorer Options
•  Select language button

•   Select language Preferences
• 
•   Add language you want to enable (Arabic)

• Move up preferred language in the list.
•  Now SharePoint will open automatically in selected language 

     My Site Language Preference

•       To enable this feature you need to enable user profile service. And my site host
•        Then log in to the SharePoint site and click on My settings 

• 1     Select edit profile and select Language and Region Option

•        In the language selection in Display Language Section you can select the language you want to display your pages

There is nice article in following MSDN BLOG