Exercises *sometimes* get ahead of the lessons!
You are probably aware of this, but this is beginning to become a bit of a frustration. New material needs to be introduced, either through the exercises themselves, or through the intro matter at the beginning of lessons, rather than lunging it upon the student unexpectedly.
I am now in, like, the 3rd tier of German and I'm starting to run into this frequently. One example is "Noch einen bitte." If this has been introduced before now, I can't find it in any of the intro material to the lessons I've taken so far, and I've gone back through nearly all of them looking for where I may have forgotten this.
If you believe it WAS introduced to me already, but somehow I forgot, please direct me to the intro material where it was first presented.
BTW, I don't mind if you once in a while slip in some new words, but I would hope these are "easy" and not requiring some firm understanding of a somewhat complex concept not yet covered. I think the source of confusion in the example I cited might be related to not having covered the three different types of inflection (strong, weak, mixed); I know that is coming but it certainly has not been covered with respect to numbers that I can recall (but help me if I have overlooked it).
Then there were the examples of "Ihr beide, bitte" and "Hallo, Ihr beiden" -- dative case (I'm guessing) had not been presented yet. I am thinking the latter is dative because I actually have quite a bit of German study behind me from ancient times in Uni (in case it is the speaker apparently saying "hello to you both," roughly).
One “problem” is that grammar and idiomatic expressions are so complex and include so many aspects that they simply cannot be officially introduced and explained in a section of their own within Duolingo. Try googling those sentences to find where and how it is used, and maybe find some grammar websites ecplaing more about it. It is also not a bad idea to have a grammar book on hand in physical or digital form. Or you can ask in the language-specific forum for input. There are some extremely helpful native speakers out there!
For unknown words you have the hints when you move the cursor or you finger over them
Duolingo was meant to teach language through immersion, that is, your are supposed to be confronted with new material all the time to “automatically” widen your knowledge without having to consciously study it. That concept works better for some languages and language aspects than for others and for some people better than for others.
Are you doing a practice (re-strengthen) exercise?
This also has been on the old system (pre-crown), that NEW words/phrases get randomly "introduced" (shown) in a review exercise, which have not been offically introduced in skill (L0) lessons.
No matter what button you have pressed (new crown lesson, global practice, skill practice) it can happen all the time, that DuoLingo adds "new words/phrases" to your words list (or shows them and adds not to your user DB).
You can have finished your tree, only strengthen it, but still you will see from time to time new "words".
Hi Thomas! No, this is happening during the regular exercises in the units.
I don't mind if Duolingo tosses in some new words from time to time, so long as the general instruction about the use of those words has already been presented somewhere previously. The "beide" versus "beiden" examples are precisely the kind that drive me batty. I've researched some of these issues all over the internet and have not found explanations yet.