I have felt the same! I doubt that I will speak (or write) it well without having a real human being for feedback, but I will probably be able to muddle through reading and getting the gist of it.
LOL — If I ever visit Germany, I can pretend I am a deaf-mute and signal for people to write it out for me!
German has several words for "you". Annoyingly, one of them is the same as the word for "they": Sie. This is used for polite/formal situations instead of using du. To make things worse, the word for "she" is also sie, but it's easier to identify as it changes verbs in a different way.
When it's written, you can tell them apart because the one meaning "you" always has a capital letter, even in the middle of the sentence. But yes, sometimes it can still be ambiguous without context.
Duolingo covers it more in later lessons, but it appears 'out of sequence' in this bonus lesson.
"sie" would not be capitalized to mean "them". "Ich verstehe sie nicht." Only in the beginning of a sentence (as a subject) would "Sie" be used as either formal form of "you" or "they". "Sie verstehen mich nicht." is either "You do not understand me." or "They do not understand me." and you would know which by previous conversation. ("She understands..." would be "Sie versteht..." and again "sie" would not be capitalized to mean "her".)
Yes... sort of. German doesn't use "helper verbs" when negating in the way that English does. In English, "I understand you not" sounds unnatural, because our language uses the phrase "do not" to negate. But in German (and every other Germanic language I can think of, excluding English) you simply negate the verb: "I understand you not."
As for why this is the case, it has to do with the large number of languages that have influenced English over the years. This particular construction, if I recall correctly, can be blamed on Gaelic.
almost correct, where there are two verbs in a sentence, one must be in the second position and the other in last position; unless you are asking a yes/no question. The modal verb 'kann' is in the 2nd position after the subject 'ich'. The second verb is ALWAYS in the stem form, also know as the basic form. The stem form of this verb is verstehen.
Verbs are conjugated, in this case: ich: verstehe, du: verstehst, er: versteht, wir: verstehen, Sie/sie: verstehen. However, like I said above, the verb at the end of a sentence does not get conjugated and only takes the stem form.
I hope I explained that clear enough.
Sie = "you" (formal)
sie = "her"
sie = "them"
When you see this sentence written, you can tell because it uses capital Sie in the middle of a sentence that it must mean "you" (in the formal way).
If you heard someone say this sentence, you would have to use context to determine which of those three meanings it should be.
"I understand you not" should be a correct answer. Modern English allows one to say this sarcastically and it still be easilly understood due to sylistic convention.
So for example, if I were to make to my father the strange utterance "Dem pickles're on the winder sill, Pop," I might expect to hear back, "I understand you not!" Which can be read as "I understand you naught!"
The antiquated nature of the phrase should not prevent it from being a correct answer. I would contend that it is a true friend as far as analogues between languages go.
Why would anyone ever say "I do not understand you" when attempting to flirt? I guess if you were saying "I do not understand you, but I want too" it would actually make sense. My point is, I believe most would relate to the sentence: "I understand you" more for flirting because one says that when they are trying to express comfort and understanding.