Is there ever going to be a Klingon course for mobile users?
Hol: Hoch jaghpu'Daj HoHbogh SuvwI' yIvup
Pity the warrior that kills all his enemies!
Though in "kangalanguage" : there is need to show patience. It is always the intention that all courses will be available for mobile users. Both for android and iOS.
Please note, I am a volunteer here, and can not speak for Duolingo. This is In My Opinion (IMO).