actually, duolingo teaches rather the grammar and common usage by giving so many likewise structured sentences. vocabulary has secondary importance. and it's a good way to learn a language, in my opinion. one can learn these birds from any online or printed dictionary, but it's hard to show the usage and grammar. drunk parrots are funny and it makes your mind to remember the lesson anywise.
I use Duolingo to learn vocabulary too, for instance, in languages for which I already know the basic grammar structure, so, I really think it's a flaw.
The comment is right, even if it's very fun to have drunk parrots, when they teach us a noun, they should teach us with it the category of noun, like "birds", I do agree.
As, when they teach us plurals, they should first teach us singulars.
I don't agree that vocabulary comes in 2nd comparatively with grammar, and is not so important in a course. It's natural to focus on both at the same time.
Learning with sentences, and learning from a dictionary doesn't have the same weight in my memory. The fact to compose sentences make the vocabulary stick to my brain. It's the reason why I use this app.
When I try to learn from a dictionary, I always try to compose sentences to make the vocabulary enters my brain more deeply.
I love Duolingo, but one of the big flaws is that the things are often introduced in random order, and not in a beginner-friendly, teaching-friendly, memory-friendly order. (see how cases and subjonctive were introduced so early).
Note: Owls are coming soon. In the lesson, and they are really naughty.
I love "psittacus ebrius", they are fun, but they are a bit too many, as now, this sentence is sticky in my head, and it's not fun, I would have preferred to remember other Latin structures. (not complaining for the exhuberant style, I love it, but for the frequency, other exhuberant things can be.) Am I alone?