How to reset Outlook folder names or language
Open a Command Prompt: Start > Run > cmd.
Enter: c: and hit Enter to make sure you are on the C drive.
Enter: cd "\Program Files\Microsoft Office\OFFICE11"
Enter: outlook /resetfoldernames
The folder names are now reset.
To reset Outlook folder names or language, manually via MFCMAPI:
Extract the downloaded zip-file and run MFCMapi.exe.
Press OK on the introduction screen.
On the main menu click on Session and choose Logon and Display Store Table.
Select the mail profile for which you want to change the folder names. If you are not familiar with this dialog, simply press OK, as the default suggested mail profile name is the one that you normally open Outlook with.
An overview of your mailbox stores in Outlook is displayed. Look at the Default Store column and select the mailbox store that has its Default Store property set to True.
A new window opens with a list called Root Container. Expand this list by clicking on the plus icon next to it.
Expand the tree called Top of Outlook data file.
Select the folder for which you want to change the name.
Click on the folder again. The name should now become editable.
Type the new name for the folder and hit Enter.
Repeat step 9-11 until all concerning folders are renamed.