In Mac OS X "Tiger" versions 10.4 to 10.4.2, you can't deselect an application's primary system language in the Info window (the window you see after selecting an application in the Finder and choosing File > Get Info). For example, if you have German set as your computer's primary system language, the "German" checkbox in the Languages section of the Info window will be dimmed.

To resolve this issue, update to version 10.4.3 or later. After updating, you'll be able to deselect the primary system language as long as at least one other language box remains checked. When only one language is checked, it will remain dimmed until at least one other language checkbox is selected.

If for any reason you're unable to get 10.4.3 immediately, you can follow the workaround presented below. We're going to assume that German is the primary system language and that you want to use Logic in English in this example, but the same steps apply for other language combinations.

1. From the Apple menu, choose System Preferences.
2. Click International, then click the Language tab. The computer's primary language is listed at the top of the list (Deutsch in this example).
3. Drag English to the top of the list.
4. Quit System Preferences.
5. Log out of your computer (from the Apple menu, choose Log Out your_name), then log back in.
6. Select the desired application in your Applications folder.
7. Choose File > Get Info.
8. Click the Languages disclosure triangle in the Info window.
9. Deselect the German checkbox, then close the window.
10. Go back to the International preference pane, but this time drag Deutsch to the top of the list, leaving English in the second position.
11. Log out and back in again so that the language change takes effect.

Now your application will use English, even though the primary system language is German.