I love Duolingo and I am learning so many new things, but i think that it needs some languages from other parts of the world besides Europe. So, if there is anyone out there who can speak English and a Non-European language, it would be great if you could get it to Duolingo. Arabic, Cantonese, Hebrew, Japanese, Turkish, Swahili, Somali, Africaans, Tagalog, Amharic, etc.
A number of Asian languages courses are already on their way. If there is an English from language X course they will make a language X from English course once the first one makes it out of beta.
So courses teaching Chinese, Japanese, Arabic , Indonesian, Hindi and many others will (eventually) be available.
Definitely on board with this idea, particularly the African language lessons, which are hard to find online. So far, I've found mostly Zulu and Swahili.
I'm looking forward to a Duolingo that teaches ALL the major languages of the world. :) It will come, one day someday.