"Sofia mentioned to me that she was jealous."
Translation:Sofia menciis al mi, ke ŝi ĵaluzas.
Ah. Ok. So if I'm understanding correctly. The Esperanto sentence makes it clear that she was jealous at the time of the mentioning. And English can't make the distinction between "Sofia menciis al mi, ke sxi jxaluzas" and "Sofia menciis al mi, ke sxi jxaluzis", that latter meaning she mentioned to me that she was jealous some time before the mentioning?
Esperanto's simple past can, in general, represent either English's simple past, present perfect, or past perfect (pluperfect).
The problem with translating your sentences is that English does not have a past tense further back than pluperfect :)
Sofia menciis al mi, ke ŝi ĵaluzis = Sofia diris al mi: "Mi ĵaluzis". Sofia said to me: "I was jealous." Sofia said to me that she had been jealous.
Sofia menciis al mi, ke ŝi estis ĵaluzinta = Sofia diris al mi: "Mi estis ĵaluzinta." Sofia said to me: "I had been jealous." Sofia said to me that she had been jealous.
Because we can't turn the "had been" into one tense further back in the reported speech ("that she had had been jealous?"), the English translation ends up being the same.
I'm not sure what you mean. But if you mean that she was jealous when she talked about it and she still is jealous. Well, when she made her statement it referred to the present from her perspective situation, then the translation "Sofia menciis al mi, ke ŝi ĵaluzas" is proper. If nothing has changed, she should still be jealous. But notice that we can verify it only when we know the current situation, thus we have to asses it form the present for us perspective but for her it is future which she couldn't know.
If she made the general statement, then she would also use the present tense. But notice that it could also change since the time when she talked about it.
The sentence you've given here is actually not considered proper English. I can see using that with the implication that Sofia is still jealous, but in general, reported speech in English matches tense (unless you put the thing in quotes, in which case "she" would be "I").
Really though, this is more of a prescriptive rule than anything hard and fast about the way native speakers really do it.
I wouldn't call that a clear distinction though. The first sentence is ambiguously past or present at the time of the mentioning. The second sentence is an adjustment that could make things a little more clear for the listener, but it also colors the meaning a bit to use the perfect aspect like that. No big deal, of course, and as mentioned, Esperanto does without this minor distinction most of the time.
Everywhere else in the course, the usual English spelling, "Sophia" has been accepted. For some reason, here it is counted as wrong. I have reported it, but nothing has changed.