Below you will find a video that shows Office 2013 users how to install and configure an Office 2013 Language Interface pack on Windows 8. I am installing a Basque (Euskara) Office 2013 Language Interface pack on English Windows 8 as an example.
The Office Language Interface Pack for 2013 (LIP) is a translated User Interface that installs on top of a licensed copy of Microsoft Office 2013. The Office Language Interface Pack for 2013 (LIP) can be downloaded and installed for free. Once the Office Language Interface Pack for 2013 (LIP) is installed and configured as in the video below, when you restart Microsoft Excel, OneNote, Outlook, PowerPoint and Word 2013 the User Interface will be translated in the language you installed. You can also use the Spell-Checker in that language.
Top Tip - make it full screen!