If you add information to your tree in 2 languages, you must make sure to add all the info in both languages, otherwise it will appear as Unknown. You can check what languages are in your tree if you open your project in Family Tree Builder and go to Tools> Languages. Make sure to set the same display and primary data language, even if you have a secondary data language. If you right-click on that window and go to Manage data languages, you will see how much data is in each language. You can choose to copy all info to one language or add all of it in both languages.
Please also see the following post in our FAQ in English regarding this issue: