I was really excited coming back to Duolingo for the first time in probably a year to see that Navajo had been added as a language. I started on it right away, but I've since seen a few mentions from a while back of the course having spelling and grammatical errors. Have these been fixed now, and if not, how severe are the mistakes? I don't really want to devote my time to learning as much of the language as I possibly can on Duolingo if I'm going to be learning it incorrectly.