For me it is really easy to learn (yet) Spanish (from English) on Duolingo because the words order are mostly the same. I like how we use the same words in multiple sentences until it sticks into your brain. Bonus: I speak Romanian too, so there are some similarities in some words there too. But I sucked learning Russian on Duolingo because I couldn't learn the writing. It's way too difficult to learn it on Duolingo.