how about Esperanto?
It would be really nice if any one of the Duolingo higher-ups would make the preparations to allow volunteers to create an Esperanto course, as I do want to learn Esperanto on Duolingo
Why should languages need to be practical to be added to Duolingo?
Well I guess it makes sense since it was created trying to give people the oportunity to learn a language without paying for classes. I would consider most important those which are more practical, either way I never said this was a reason why it should not be added.