theory before practice
Direct beginning with practical exercises ( like questions, translations) with words you don't know is perhaps not the best way to learn: i think you should begin with showing full list of vocabulary, and then let decide when the student is ready to do some exercises
I think the method they are using is designed to introduce you to vocabulary in a less overwhelming way, while creating connections between words and structure. When you drop new words in, it forces your brain to create a link between that word and the last word you saw used this way, and how it fits or alters the structure of the overall sentence. That is why they don't mark you down for hovering over words to get the meaning.
In the real-life exercises, this is obviously affected by the complexity of the words. I would be curious to know how the algorithm they use pulls down choices depending on your level of skill (as it sometimes seems beyond mine).
This is, of course, only one method of learning. It is much more akin to immersion than a full list of vocabulary can provide, but up-front knowledge is certain to work better for some people.
i partially agree with you, but you really never can translate a word in an other linguage you unknow, unless you should use google translation; it 's why everybody should be free to follow the best way for him, sometimes the way you are proposing ( what asks a preexisting knowlegde) , sometimes translate after a full access to the whole concerned vocabulary
Could you be more specific about why you think that it could be better? Don't you enjoy this way of learning or do you think people in general would benefit from a different method?
I really like this way of getting a feeling of how a language works instead of having to think about what grammatical rule to apply or which word to remember from a list. Your suggestion is very similar to the way in which schools teach languages; a method that does not work for everybody. I think that duolingo allows users to learn a language in a more natural way while offering the joy of using real language right from the start.