"There is a big mountain between those Japanese cities."
Translation:Van egy nagy hegy azok között a japán városok között.
My answer: "Van egy nagy hegy azok a Japán városok között" was not accepted. It sounds right to me.
So my question is this: Is it necessary to say the word, "között" twice in such a sentence? Or is it an optional, stylistic difference - in which case both answers would be correct?
I found an entry on e-nyelv regarding this topic, and it agrees with Shamarth that the postposition needs to be repeated. If you'd be so kind, when did you get that information and how old is/was your teacher? It might be a thing in development.
But maybe your teacher meant instead that you could say "azon japán városok között". Using ezen/azon instead of the demonstrative construction is possible as well, even though it might be somewhat old-fashioned.
So many possibilities! I didn't know about that ezen/azon one...
If I understood well this time - and if I'm able to explain it with my poor English -, the rule would be:
1/ To repeat the postposition if this postposition doesn't call for a verb complement.
Ex: "E miatt a fiú miatt." Because of this boy.
2/ But if the postposition needs a verb complement, then you don't repeat it.
Ex: "Ezzel a fiúval együtt." Together with this boy. [and not : "Ezzel együtt a fiúval együtt."]
" Ezen a kis fehér házon kívül. " Outside of this small white house. [and not : " Ezen kívül a kis fehér házon kívül. "]
3/ Now, here where it becomes complicated. I found an article written by a linguist (I give the link, but unfortunately it is in French: http://www.ddl.cnrs.fr/fulltext/Creissels/Creissels_2006f.pdf )
On page 27 you find explanations on the use of the postpositions, and the example (19) d. is a construction where " mögött " is not repeated. My problem being that this example comes with an asterix, and I found nowhere in the article what this asterix means...
(19) a. Ez a kis fehér ház.
b. Ez-en a kis fehér ház-on.
c. E mögött a kis fehér ház mögött.
d. *Ez a kis fehér ház mögött.
e. Ez-en a kis fehér ház-on kívül.
4/ The teacher is in his thirties. ^^
You have to make a difference between postpositions on one side, and adverbs on the other side. Only postpositions (and suffixes) get repeated. Együtt and kívül are adverbs.
For the examples you gave, it's pretty easy to decide, because a noun can only have one rag-suffix ("case suffix", the type of suffix that gives a noun its grammatical role in a sentence) or a postposition. -val and -on are rag-suffixes, so the words that come after cannot be postpositions and are not repeated.
(To make a list, the rag-suffixes that are used in this course are: -ba, -ban, -ból; -ra, -on, -ról; -hoz, -nál, -tól; -val, -nak, and -t. That are almost all there are in Hungarian. The document you linked lists some more on page 19.)
In linguistic works, the asterisk usually means that the listed form is incorrect. For example if it says
d. *Ez a kis fehér ház mögött.
it means that you can come up with this phrase when making sentences, but it's not a valid form for some reason. In this case, it's grammatically wrong, because the ez needs to copy the mögött, at it's shown in 19 c.
Ah, right, I see it. "Les postpositions du type kívül".
In one of the bullet points on page 26 he gives the example of "kívül a házon". I wouldn't really call it a "postposition" if it can appear in front of the noun. The terminology is not clean-cut there.