I think a windows phone app for duolingo is better
As you know windows phone increase more and more quickly now, some users of windows phone want a duolingo app for windows phone,like me, so i think it will be better when an app for windows phone comes :)!!!
What's "better" supposed to mean in this context? I am not opposing your wish for an app for your OS but I disagree with your premise. Windows phone is around a market share of 5% and I don't see this increase right now. With limited resources of the duolingo crew it's natural to concentrate on the big players to get the most impact. Let's still hope they find the time now and then to make you happy too ;)