Which registry key do I need to edit to change the default spellcheck language in Office 2003

Change the default language setting
You can change your default settings in Microsoft Office to have them match the default settings of a different language.

In Microsoft Windows XP, on the Windows Start menu, point to All Programs, point to Microsoft Office, point to Microsoft Office Tools, and then click Microsoft Office 2003 Language Settings.

In Windows 2000, on the Windows Start menu, point to Programs, point to Microsoft Office Tools, and then click Microsoft Office 2003 Language Settings

Click the Enabled Languages tab.
In Windows XP, in the Choose the language that defines default behavior in Microsoft Office applications box, select the language you want, and then click OK.

In Windows 2000, in the Default version of Microsoft Office box, select the language you want, and then click OK.

A message appears describing the effects of the change. To continue, click Continue and lose customizations.

I need to be able to automate this change and would like to know in which registry key these settings are kept.

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Control Panel\Extended Properties\{305CA226-D286-468e-B848-2B2E8E697B74} 2
The allowed values of category IDs are as follows: • 0x00000000 : Other Control Panel Options (any tool that does not specify a category ID is placed in this category)
• 0x00000001 : Appearance and Themes
• 0x00000002 : Printers and Other Hardware
• 0x00000003 : Network and Internet Connections
• 0x00000004 : Sounds, Speech, and Audio Devices
• 0x00000005 : Performance and Maintenance
• 0x00000006 : Date, Time, Language, and Regional Options
• 0x00000007 : Accessibility Options
• 0xFFFFFFFF : Do not put the tool in any category (for special tools such as Add/Remove Programs which only start directly)
For example, this is how the Accessibility tool would be registered:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Control Panel\Extended Properties\{305CA226-D286-468e-B848-2B2E8E697B74} 2
"%SystemRoot%\System32\access.cpl"=[DWORD] 0x07
For tools that are implemented as shell namespace extensions (for example, Fonts and Scheduled Tasks), the category ID is specified in the registry under the CLSID entry. For example, the registry entry for the Administrative Tools folder is:
HKEY_CLASSES_ROOT\CLSID\{D20EA4E1-3957-11D2-A40B-OC5020524153} "{305CA226-D286-468e-B848-2B2E8E697B74} 2"=[DWORD] 0x05