Heute habe ich Konjunktiv II gelernt, aber ich finde das ein bisschen kompliziert zu verstehen...
Enough of my bad German. So, I am confused between when to use wäre or würde. Zum Beispiel: (What is the difference?)
- Wenn er doch heute kommen würde!
- Wenn er doch heute gekommen wäre!
AUCH
- Ich würde gern.... feiern.
- Ich wäre gern.... feiern.
Ich freue mich auf Ihre Antwort!
Every German verb has two ways of forming the Konjunktiv II. The first one is what linguists call synthetic, i.e. via inflection. For strong verbs, these forms look like past forms, but with an added ending -e and umlaut if possible:
past indicative - past subjunctive/Konjunktiv II
hatte - hätte
war – wäre
kam – käme
ging – ginge
Note that some verbs have different vowels in the past indicative and past subjunctive: stehen, stand, stünde.
For weak verbs, past indicative and past subjunctive are identical.
Als ich damals in Italien lebte … (=war, past indicative)
Wenn ich jetzt in Italien lebte … (=leben würde, past subjunctive/Konjunktiv II)
Note that although the form is called past subjunctive, it refers to the present and the present only! This will be relevant below.
Probably because this ambiguity between past indicative and past subjunctive is hard to tolerate, a second way to form the Konjunktiv II has developed. This is what linguists call analytic, i.e. by combining two words, namely a form of würde plus the bare infinitive.
würde haben, sein, kommen, gehen, leben, …
So far, so good. Let's apply this to your examples.
Wenn er doch heute kommen würde!
Wenn er doch heute gekommen wäre!
The first example is simply the analytic Konjunktiv II of kommen. It is desirable for him to come, but it is not yet known whether he will do so or not.
The second example is the synthetic Konjunktiv II of (gekommen) sein. Above I mentioned that the Konjunktiv II by itself always refers to the present. However, in this case a perfect auxiliary (sein) appears in the Konjunktiv II, which means the second example refers to the past: It would have been desirable for him to come, but he did not.
The other set of examples shows the same kind of difference.
Ich würde gern feiern.
Ich wäre gern feiern.
The first example is the analytic Konjunktiv II of feiern. I have the desire to party, but am not partying at the moment.
The second example is the synthetic Konjunktiv II of (feiern) sein. However, sein plus infinitive is a tricky construction. It could be interpreted as
Ich wäre gern feiern gegangen.
with wäre gegangen as the synthetic Konjunktiv II of (gegangen) sein, with the expected meaning: I would have liked to go partying, but did not in fact do so.
If ellipsis is ruled out, it could be an instance of the construction discussed in this question. The basic meaning is telling someone where you are or will be, or, in the Konjunktiv II, where you would like to be but are not.
Ich wäre ja schon lange feiern, wenn meine Freunde mich pünktlich abgeholt hätten!
=Ich wäre schon lange auf der Party, wenn …
To be frank, the first time I read
Ich wäre gern feiern.
I thought you had mixed the synthetic Konjunktiv II of sein (wäre) and the analytic Konjunktiv II of feiern (würde feiern). Could this be the case?
Ich wäre auch auf der Party, wenn ich könnte.
Ich würde auch mitfeiern, wenn ich könnte.
In your first example:
In your second example, the sentences are fine, assuming they express what you want:
Basically, both sentences (1) refer to a future that may or my not come, and in connection with "wenn doch" oder "gern" it is a desired future. The sentences (2) refer to something that might have happened in the past, but didn't, here again something desired.
The desired part is not from the grammar but from the additional context of your examples.
Again (1) may still happen, (2) didn't happen, but here it is not about a desired result (unless context implies you talk about someone you don't like).
Würde is a Konjunktiv II form of the verb werden, while wäre is a Konjunktiv II form of the verb sein. Both are used as auxiliaries in your examples.
Ich weiß, dass er heute nicht kommen wird. – Wenn er doch heute kommen würde!
What we have here is the Infinitiv kommen and the auxiliary werden. This is Futur I tense, in both sentences. The first sentence uses the Indikativ mood. It's a fact you know he won't come. In the second sentence you imagine a future in which he comes today. You know better, it's counterfactual. That's why you have to use the Konjunktiv II mood.
Ich weiß, dass er heute nicht gekommen ist. – Wenn er doch heute gekommen wäre!
What he have here in contrary is the Partizip II gekommen and the auxiliary sein. This is Perfekt tense (in German, this conveys the past), in both sentences – kommen uses the sein auxiliary for its Perfekt tense! The first sentence again uses the Indikativ mood. In the second sentence you imagine a past (Perfekt again!) in which he came today. You know better again, it's counterfactual. That's why you have to use the Konjunktiv II mood again.
Ich weiß, dass er heute nicht kommt. – Wenn er doch heute käme!
This is Präsens. The first sentence is again in Indikativ mood, the second in Konjunktiv II mood. Despite the different tense, the marker word heute makes it clear this is about the present and the near future. German Präsens allows that use.
That Präsens Konjunktiv II by definition has exactly the same meaning as Futur I Konjunktiv II. For most verbs the Konjunktiv II forms are the same as the Präteritum forms. German speakers prefer the Futur I Konjunktiv II (würden+Infinitiv) for those verbs.
(Of course, you can also mix up the sentences and switch tenses, too.)
Please understand in contrary to e.g. English subjunctive, German Konjunktiv isn't a time form but a mood. It can be mixed with several time forms.
Ich würde gern feiern. (Futur I Konjunktiv II)
Ich feierte gern. (Präsens Konjunktiv II or Präteritum Indikativ – only used for the latter purpose)
Ich hätte gern gefeiert. (Perfekt Konjunktiv II)
Same as above, but feiern uses the haben auxiliary for its Perfekt tense, as most verbs.
Ich würde gern feiern gehen. (Futur I Konjunktiv II)
Ich ginge gern feiern. (Präsens Konjunktiv II – unique, but too odd, nobody talks like this)
Ich wäre gern feiern gegangen. (Perfekt Konjunktiv II)
As an additional trick, this uses gehen as a modal verb. Gehen is another common verb that uses the sein auxiliary for its Perfekt tense.
