I am having a little trouble with vowel harmony; specifically the lesson with plural and the accusative cause. Does any have any good resources on vowel harmony?
I wrote in another comment a bit about vowel harmony: https://www.duolingo.com/comment/17406200
I also mentioned the plural with its possible connecting vowels for adding the plural sign -k.
For the accusative you use the same ones, beside those words, where adding the accusative sign -t results in a speakable word :-)