Words not highlighted

Hello, I imported a book and the words are not highlighted. In settings/highlight style it “default” is selected.

Edit: I think I realize that it is because I have “900 new learned words” - I don’t know how this happened, but I haven’t learned/accumulated 900 new words. I probably need to reset the language or delete my account and start over?

You can reset a language and start over under Settings > Languages.
Please note when you complete a lesson, all blue words will be moved to known. It will also happen when you switch pages.
You can disable “paging moves to known” feature under Settings > Reader.