Folder names are incorrect or displayed in an incorrect language in Outlook...

Use Outlook Web App to reset the default folder names:
 

1. Exit Outlook.
2. Log on to Outlook Web App by using your credentials.
3. Select Settings (the gear icon on the right) > Options > General (expand the list in the left navigation pane) > Region and time zone.
4. On the Regional and time zone settings page, change the language, select the date and time format that you want to use, select the Rename default folders so their names match the specified language option, and then select Save.
5. Exit Outlook Web App.
   
   Note If your preferred language is already selected, you may have to select any other language, save the setting, reset the setting to your preferred language, and then save the setting again.
6. Restart Outlook.

Use the /resetfolders switch to restore missing folders at the default delivery location. To do this, follow these steps:
 

1. Exit Outlook.
2. Open the Run dialog box:
   • In Windows 10, Windows 8.1, and Windows 8, press Windows Key  + R.
   • In Windows 7 and Windows Vista, select the Start button > All Programs > Accessories > Run.
3. In the Run dialog box, enter the following command, and then click OK:

   Outlook.exe /resetfolders