If you have installed a language that you find you no longer need you can uninstall it without affecting the WordBanker installation although there is no great benefit in doing so as languages occupy very little disc space.
To uninstall a language go to Language Manager and click "Uninstall Language" from the menu at the top.
Select the language you want to remove from the drop down list. In most cases you will want to delete the testing data for that language but if you prefer you can keep by checking the appropriate button.