How to Change the Language of the Ribbon and Commands in Microsoft Office 2003 with MUI 52
Microsoft separates between a language pack (LP) and a language interface pack (LIP). As per Microsoft, a LIP is a "high-quality, localized "skin" for emerging or minority language markets. [...] A LIP provides the desktop user with an approximately 80% localized user experience by translating a reduced set of user interface (UI) elements. A LIP [...] has a dependency on a base language pack of Windows.The difference between an LP and a LIP is "the level of localization in comparison to language pack (LP) packages: LIP packages provide the desktop user with the most frequently accessed user interface and basic user assistance support (help files). In addition, a LIP is installed as a language add-on on top of an existing LP with base language dependency (Catalan LIP can only be installed on top of the Spanish or French LP, Welsh LIP can only be installed on top of the English LP). In addition, once a LIP is installed, switching the user interface between the LIP language and the LP base language is possible for users on all versions of Windows.
Microsoft Office 2003 Multilingual User Interface Pack MUI 52
A Language Preferences interface in Access, Excel, OneNote, Outlook, PowerPoint, Project, Publisher, Visio, and Word is accessible in the Backstage view and replaces the language customization interface seen in previous versions of Office. The new interface provides information about currently installed language packs and their related components, hyperlinks to download additional content, and a new ScreenTip Language feature that allows users to customize the language of tooltips.