The huge amount of errors beyond the second lock in the German language section
I am finding quite a large and frequent amount of mistakes in the German language tests beyond the second "lock". Some of these are also fundamentally incorrect, such as disallowing the expansion of an abbreviation. For example, I wrote "cannot" as a translation and it was marked incorrect because I didn't enter "can't," which seems completely counter-intuitive and uninformed. Additionally, within the German language examples themselves and what DuoLingo considers the more acceptable definition of a word is in fact not the accepted translation in the languages and linguistics community. I try to "test out" of a level and fail time and time again due only to the fact that the answers required are either inaccurate or at worst plain wrong. What systems and mechanisms are in place here to prevent such things and why is it that with each exercise I complete I feel that I'm informing whoever is in charge of German of the basics of both the German and English languages? I am submitting an average of 4 corrections per exercise and feel anything beyond the first third of the course has been poorly constructed. As a teacher of German and a lifelong student and native speaker, I would like a resource that I can provide my students with, however this doesn't really seem to be the place to go for accurate language learning.
Think about it this way: the reason there are so many errors later on is because fewer people stick with language study and get that far. That means fewer people send in "I still think I'm right!" feedback and the program then has a smaller collection of correct options that it will recognize. The more people doing upper-level lessons (and giving feedback), the better it will be for future users.
In the Spanish section I've noticed one time "cannot" was marked wrong because duolingo wanted "can not". Best I can tell in English "cannot" vs "can not" is totally optional. Anyway the only way to get all the correct solutions into duolingo's database is to submit them. The problem is for every expert like yourself there are 100+ other people filing reports for various reasons. I think duolingo CEO mentioned on reddit that most the users filing reports turn out to be wrong so the company probable has assigned reviewing all reports to a low priority. It would be nice if they would give a teacher like yourself a higher priority.
'Cannot' is a simple negation of 'can', while 'can not' adds emphasis to the negation.
"Cannot" is far more common. My dictionary says the following about the usage of the contracted and the separated from: "USAGE Both the one-word form cannot and the two-word form can not are acceptable, but cannot is far more common in all contexts. Indeed, can not has come to be so unusual that it may be read as an error. The two-word form is advised only in a construction in which not is part of a set phrase, such as 'not only . . . but (also)': : Stevenson can not only sing well, but he paints brilliantly." (source: New Oxford American Dictionary)
Yes, 'cannot' is the common form, but, through usage, and greater familiarity with the contracted form, many people expand it to 'can not' in more formal expression, when usually the single word form is more appropriate.