"Sie" has different meanings: she, you (formal) and they.
You can tell them apart by:
1) the verb. "Sie" in the sense of "she" is used with a singular verb (3rd pers. sgl.), and Sie/sie in the sense of "you" and "they" is used with a plural verb (3rd pers. plural).
2) the capitalization. When "Sie" means "you", it is always written with a capital "S". When "sie" means "she" or "they", it is only capitalized when it is the first word in a sentence.
Mag sie das nicht? = Does she not like that?
Mögen sie das nicht? = Do they not like that?
Mögen Sie das nicht? = Do you not like that?
Yes, context alone.
Usually, it's clear whether you had just been speaking about each other or about someone else.
The verb mag-as in ich mag (I like) is cojegated to my gen. The en is the clue that this sie means they. I googled the complete German declination tables. I keep a binder & print out as I need to, other things like word order & sentence structure etc. Hope it helps.
"They don't like that?" was my answer. Sometimes I understand the meaning, but it's hard for me to think about how it would be phrased in English :/
Just because it isn't proper English grammar, it shouldn't be wrong. Being a native English speaker, I answered the same way, and it told me I was wrong. Learning German has been changing my English grammar.
You don't translate literally. You translate to what a native speaker would normally say.
I went with “Don’t they like it?” and it was wrong. Would my translation be “Mögen sie es nicht?” or would that sound weird in German?
"Don't they like it" and "Do they not like it" are exactly equivalent in meaning, however, the second one sounds very old-fashioned. They should always be translated the same way into other languages.
I translated this same sentence once before as "Do they not like it?" and was given credit for it.
I wrote "Do they dislike that" (I have always used dislike as a translation for "moegen ... nicht" as it sounds most normal to me) and it was marked incorrect. It has been accepted in other circumstances just not here. That leads to my other question, is "moegen ... nicht" the only way to say dislike or is there a better way to say it?
Can this structure of sentence be used in the same meaning as a tag question? Like, you ask if someone doesn't like something, but actually you just want to confirm that this something is adorable.
Why not "Mögen das sie nicht" ? Kind of confused on positions of some words.
I wrote "Mogen (with an umlach on the o) Sie das nicht" and it was accepted. Is my answer correct and if it is correct should it not mean "Does she not like that?"
I put "Don't you like it?" which is wrong because "sie" only means "you" if it's capitalised... but would I be correct in guessing that the only difference is in written German, while the spoken sentence itself is ambiguous?
That's right - the difference is not audible and is only discernible in writing.
That's not the neutral way to phrase a yes–no question in (standard) English -- you would need the helping verb "do" for that: Don't they like that? or Do they not like that?
I am an English speaker, I found this confusing, purely because of the word order. I instinctively thought that the answer is "They do not like that" I know that there are rules about word order etc the only clue that it was the question was the question mark - Do they not like that was the result when learning any new language most people, myself included, tend to concentrate on learning new word translations the subtleties of German Grammar are simply far too exasperating Mark Twain was correct with his essay regarding learning the German language - https://www.cs.utah.edu/~gback/awfgrmlg.html
A literal word by word translation would read as "Like they that not" Getting the correct word order here is mostly guesswork based on the question mark, Earlier DUO suggested that NICHT usually means Never when used in this way so "Like They That NEVER?" which is even more cryptic I have now decided to ignore the "NEVER" advice given by DUO previously.
My answer was correct. Sie, in German, besides meaning THEY, also means YOU, as a formal address.
The formal you is spelled Sie -- it is always capitalised.
This sentence has lowercase sie, so it cannot mean "you".
Why is "don't they like that" wrong? It only accepts "do they not like that".
Why is "don't they like that" wrong?
It's not. And it's one of the accepted translations.
Without a screenshot showing exactly what happened, I can't say much more.
The most common cases do involve some mistake on the learner's part, though, rather than a problem of Duolingo's -- overlooking a small typo, or mistaking a listening exercise for a translation exercise.