Before importing your language strings into the Language Settings Tab you need to make sure that the formatting is correct. When you export your language string file it may include special characters depending on which languages have been enabled, therefore you need to make sure that the exported file is opened with UTF-8 encoding enabled. This encoding is widely supported and is an industry-standard. To properly open such a file in Excel, you must open a blank worksheet and select Data->From Text/CSV and open the desired file-> Choose Unicode UTF-8 from the File Origin selector.
Best Practice: Create your event first in one language and then start the other language strings.