You can download the SharePoint 2013 Language Pack here:

Foundation 2013:

Server 2013:

For Server admins, you need to install binaries for foundation 2013 LP first and run Configuration wizard, and then install binaries for server 2013 LP and run Configuration wizard

In order to change language to LP’s:

  1. enable it in Site Settings > Language settings
  2. Go to the Internet Explorer settings on your client machine (or on server) and press Language button to add language