"This easy language is difficult."
Translation:이 쉬운 언어는 어려워요.
I decided to switch it up a bit and use 해라체 because I'm not very skilled at using it, so I wrote 이 쉬운 언어가 어렵는다. I realize that I made a mistake and it should have been 어렵다 because it's a descriptive verb, but Duolingo corrected me to 어렵단다. What is that form? I don't recognize it.