I haven't gotten super far in duo's Japanese -- mostly it's been hiragana (which I deliberately learned before trying duo) -- but it tends not to explain things. But I'm also doing memrise, which is much better -- it doed break things down into components. (I dabbled in the Spanish lesson, and it has literal translation (e.g. "tu" is "you (singular, informal)" as well as regular translation ("you"). Or with Japanese, distinguishing "ni (hiragana)" from "two". Again I still haven't gotten far, but I suspect it will continue to be good.)