"Where is he calling to?"
Translation:לאן הוא מתקשר?
Disagree, it's the difference between "where" is he calling to - to the hospital, to the police, to the restaurant etc., and between "who" is he calling to - he's calling his mother, his friend, etc. That is, of course in Hebrew, the difference between Le'an - לאן (where to), and Le`mi - למי (to who)
That's a very good question.
Not being on team with the moderators I can't say how their actual decisions are made. From my experience with Duolingo however, the point is to translate correctly from one language to another.
Translating is a very tricky art. Any two languages are fundamentally different and direct straight translation exists in occasion, and often does not. This is why a sentence can get so many different translations.
Sometimes, a use of words is idiomatic, and a literal translation is wrong or unnatural.
It's not an exact science, but I'm putting in my 2¢ about how things go from one language to the other. It's my personal opinion and you may disagree. The moderators sometimes do :-)
If you search further you will see there are places where I am lenient. It is true that I put my foot down if I think the alternative is wrong. Two similar sentences are not necessarily identical inside a language, so there is no reason to translate one into the other.
As an anecdote, I remember reading about a computer program that was taught to translate between English and Russian. Someone input "the flesh is weak but the spirit is willing" it was translated there and back again to result in "the meat is rotten but the vodka is good"
In reference to your translation anecdote in another comment (unfortunately, Duo wouldn't let me reply directly under that comment). If I may refresh your memory or, possibly, improve on your sources. It's a textbook story often replicated in various resources on translation principles. It actually has to do with one seminarian's translation of Matthew 26:41 from the Latin Vulgate: "Spiritus quidem promptus est caro autem infirma." In his assignment, he rendered it as, "The alcohol (spiritus) is still prompt but the meat (caro) has gone bad." Technically correct but contextually improbable.
This is a different kind of "calling" than קרא. The root קשר has to do with connections, ties, relationships and so on. Pa'al verb לקשור means "to tie, to connect". Pi'el לקשר means "to connect, to join", somewhat similarly to hitpa'el להתקשר, but the difference is that pi'el is transitive (you connect something) and hitpa'el is intransitive (you connect yourself). That is why it's considered reflexive. So, when you call someone (on the phone, unlike קרא which means to call, when you want to get somebody's attention), you "connect yourself" to that person.
Not sure which other verbs cause you problems, but there are a lot of examples like this one, where a verb exists in several binyanim, and when in pi'el it is transitive, and intransitive, when it's in hitpa'el.