My point was that konjunktive in many cases, as in the case of sollen, is the same as imperfect past (and therefore würden + infinitive is the more common construction for other verbs, not sollen though). Sometimes soll = should, sometimes sollte = should. Depends on the context. I believe sollte is more like... i really should do it but I don't have to. Soll is more like 'muss' but someone else told you to do it. I'm still not 100% however.
I think you're generally right here. After having studied for the last month and a half in Berlin, we came across the proper usage of modal verbs. Müssen is to have to and dürfen is to be allowed to and können is to be able to. "Sollte" is a suggestion so it sounds weird coming from yourself. I can ask the teacher tomorrow.
as far as i can tell, 'ich soll' is 'i am expected to/i am supposed to', where ich sollte is 'i ought to' - sollen carries the idea of pressure from (though not necessarily obligation to) others, sollten the idea of, i guess, an independent, intellectual reason to do something. but i imagine there's probably often overlap, in the way that english modals are often interchangeable ('could', 'may' and 'might' for example)
Sort of like the Futur II Aktiv forms shown in this link? but with sollte instead of werde or würde?
yeah basically. normally i'd try and give a reasonable explanation but i've had a few and i'm not totally sure of myself anyhow -- hopefully this demonstration of tense-building might help explain it somehow?
I learn German = Ich lerne Deutsch
I have learnt german (/'I learnt German' in conversation) = Ich habe Deutsch gelernt
I should have learnt German = Ich sollte Deutsch gelernt haben
I will have learnt German = Ich werde Deutsch gelernt haben
I would have learnt German = Ich würde Deutsch gelernt haben
Does this work with all the modal verbs? And specifically, with 'will'. Would it be correct to switch out the examples you gave for soll here with will?
As in, "Ich wollte Deutsch gelernt haben" = "I have wanted to learn German".
I know that's a strange example, and it would be rarely used, but I'm asking just for an example.
this is the example they give: Sie haben den Film immer sehen wollen. = They have always wanted to see the film.
i think 'Ich wollte Deutsch gelernt haben' = 'I wanted to have learnt German' but i'm not 100% sure