Perhaps the nearest thing in English, also using the subjunctive, would be "I would like it if you were to come at nine". Note that the "were to come" is getting close to "venissi". Although the English does not exactly have the past continuous (imperfect) construction about it, it is still very close, and definitely not in the future or pluperfect.
Much better, I think.
I don't know if the problem is with the translation or the Italian original. Translation here calls for some greater latitude, I think.
Also, I don't think this kind of issue can be easily resolved, if there is indeed nothing wrong with the Italian. It just takes getting used to, perhaps.
in italian there's an overabundance of verb tenses, and sometimes the congiuntivo presente and congiuntivo imperfetto are used interchangeably. This practice is so widespread that is commonly accepted, but below you'll find the grammatically accurate explanation. (EDITED: grazie DaGot66)
Keep in mind that this is a special case translation for English, because the verb /to want/ calls for an infinitive!
Here are two phrases which hold the same meaning and are translated the same way. 1 uses the presente and 2 the imperfetto 1) Voglio che tu venga [qui] alle 9. (I'd like you to come [here] at 9: this expresses a desire for an action yet to happen). 2) Vorrei che tu venissi [qui] alle 9. (I'd like you to come at 9: this still expresses a desire for an action in the future, even if it uses the imperfect (the conditional "vorrei" calls for the congiuntivo imperfetto). How do you tell? Well because of "Vorrei", which is present tense. How would you wish for something that has already happened?)
Anyway, even when used correctly, the imperfetto stills translates to an infinitive English verb IN THIS CASE! While on the other hand Trapassato translate to a "past infinitive (?)". Consider this: 3) Imperfetto: Volevo che tu venissi qui alle nove. (I wanted you to come here at nine) 4) Trapassato: Avrei voluto che tu fossi venuto qui alle nove. (I would have liked you to have come here at nine)
Congiuntivo Passato does not apply to the special case of /to want to/, because you cannot want now for a thing in the past to have happened, it already did.
This instead is the how you normally translate a congiuntivo
presente - simple present (non credo che lo sappia = I don't believe she knows); or present continuous (penso che parta oggi = I think she's leaving today); or an infinitive in special cases like /to want to/ (see above)
imperfetto - simple past (non credo che lo sapesse= I don't believe she knew); or past continuous (pensava che partisse oggi = he thought she was leaving today); or an infinitive in special cases;
passato - present perfect (non credo lo abbia saputo = I don't believe she has heard) (but simple past may be acceptable too?)
trapassato - past perfect (non credevo lo avesse saputo = I didn't believe she had known); or past infinitive in special cases
"How can you wish for something that already happened?" We do it all the time in English, expressing a possibly different outcome: "I wish you had come at nine." "I wanted them to have known about the traffic before they started." Such expressions are usually expressing regret, or possibly nostalgia? But I have no idea what this would mean in Italian...
I think that this is referring to something that is going to happen in the future isn't it? The "vorrei" is present conditional tense (I would like) used when expressing what you would like to happen in the future. Perhaps the nearest thing in English to this sentence, also using the subjunctive, would be "I would like it if you were to come at nine". Here is a link to some Reverso context for this phrase all of which indicate a present wish for someone to do something in the future: http://context.reverso.net/traduction/italien-anglais/Vorrei+che+tu+venissi+alle+nove
right. "I wish you had come at nine." translates in italian to "avrei voluto che (tu) fossi venuto alle 9" or better "avrei voluto che fossi stato qui alle 9". So the action you perform "to wish" is also in the past, because that's what you wanted and have been wanting since. You used the past tense yourself in the example "I wanted them to have known about the traffic before they started.".
"Venissi" is a subjunctive imperfect: http://italian.about.com/library/verb/blverb_venire.htm
Not always. Especially after volere. There's an example here (see p. 34): http://books.google.com/books?id=MIH09T_1II0C&pg=PA31&lpg=PA31&dq=Italian+subjunctive+volere&source=bl&ots=nGpwzJdG5o&sig=QLGYdWAP0saWjJcoUVo3hzJafm4&hl=en&sa=X&ei=gP_pUe7-Ae2l4AO6y4HADA&ved=0CGgQ6AEwCQ#v=onepage&q=Italian%20subjunctive%20volere&f=false
No that is grammatically wrong. In Italian the present tense requires the imperfect subjunctive. But is not referring to the past so that is wrong. In any case, were this sentence in the past you would need to say "I would have liked you to have arrived by 9", but we arent talking past here
The use of the imperfect subjunctive in spoken language is another reminder to French speakers learning Italian that they cannot coast along, simply plugging in equivalent forms. In French, one can say either "je veux que tu viennes" or "je voudrais que tu viennes," with the present subjunctive used in both cases. If one were to say "je voudrais que tu vinsses," there would be titters of amusement, even though the sentence is, in fact, grammatical..
It's the imperfect subjunctive. You might read my note above from three months ago...I don't understand why you think it's "peculiar" to include it in this exercise. This is common usage. In German, one could say simply: "Ich möchte, dass du um neun kommst." But one could also say "Ich hätte es gerne, wenn du um neun kämest." Italian speakers don't seem to be conscious of using the full range of the subjunctive. When a friend and I are speaking (in German), we sometimes use the past subjunctive and then make an ironic comment about it.
Oh, good! I didn't wish to appear obnoxious! In German, as you've learned, contrary-to-fact statements (if I had known that, I would have...) in both clauses. In Italian, the imperfect subjunctive is followed by the past perfect. In French, it's past perfective (indicative) + conditional perfect. (Si je n'avais perdu mon livre, j'aurais pu me préparer pour l'examen 'If I had not lost my book, I would have been able to prepare for the exam.') In German, it's the subjunctive in both clauses. So German speakers have to learn to switch gears!