For those working with the new language versions of Lightroom, if you would like to switch languages just follow these instructions:
Windows
- In Lightroom, visit Edit –> Preferences and click on the General tab
- Select the desired language from the dropdown
- Restart Lightroom
Macintosh
Lightroom follows the operating system language preference. To change it:
- Visit the Mac OS X System Preferences and select International
- Select the desired language in the list and drag it to the top of the list
- Restart Lightroom
Thanks again for everyone’s feedback on our new updates.

In Mac OS X you can find Adobe Lightroom 2.3 RC.app and Get Info (Cmd+I) under Languages section you can deselect the languages you don’t want to use.
If you do not want to change the default language for all your applications in Mac OS X, you can use my tip and trick: http://www.juliengille.com/en/blog/2010/08/change-the-default-language-of-lightroom-on-mac-os-x/
It is working with Lightroom 2 and Lightroom 3
Cheers