German Konjunktiv II - General Subjunctive II

The general subjunctive (Konjunktiv II) is used to express hypothetical or unreal situations, and can be formed in the present tense with a form of “sein” (wären – would be), “haben” (hätten – would have), or “werden” (würden + Infinitiv – would + infintive). 

Examples: 
Wenn ich reich wäre, würde ich ein neues Haus kaufen.
If I were rich, I would buy a new house. 

Wenn ich mehr Zeit hätte, würde ich mehr Bücher lesen.
If I had more time, I would read more books. 

To form the general subjunctive with weak/regular verbs, which are verbs that show no vowel or spelling changes in any of their forms (present, past, perfect), we simply add the preterit endings (fragen -> frag -> fragte = would ask). However, this means that for most weak verbs their preterit form and their general subjunctiv (Konjunktiv II) form are identical. This is why it is common form the Konjunktiv II with weak verbs using “würden + infinitiv”. (Ich würe fragen = I would ask). 

1. Strong Verbs (starke Verben)

l pattern of strong verbs (verbs that have a vowel or spelling change in the present, past, or perfect tense) in the subjunctive is to add an umlaut to the simple past stem vowel, if the stem vowel is either “a”, “o” or “u” (geben -> gab -> gäb-, finden -> fand ->fänd-) before we add the verb subject pronoun specific verb ending. If the stem vowel is “i” (ging) or two vowels (ie -> ‘hieß”, we do not change to an umlaut, but still ad the “-e”. )

In the present subjunctive, we add  ‘-e’ to the first and third person singular (“Ich” and “er/sie/es”. In comparison: strong verbs in the simple past do not have an ending for “ich” and “er, sie, es”. 

Other strong verbs that are frequently used in their present tense subjunctive form include: kommen (to come), gehen (to go), halten (to hold), tun (to do), lassen (to let), fahren (to drive), heißen (to be called). There are several strong verbs with irregular present subjunctives, for example: helfen (to help) -> half- -> hülfe (not hälfe)

Other strong verbs that are frequently used in their present tense subjunctive form include: kommen (to come), gehen (to go), halten (to hold), tun (to do), lassen (to let), fahren (to drive), heißen (to be called). There are several strong verbs with irregular present subjunctives, for example: helfen (to help) -> half- -> hülfe (not hälfe)

2. Mixed Irregular Verbs (gemischte Verben)

The mixed verbs, which are verbs that use some of the characteristics of weak/regular verbs, and some characteristics from strong/regular verbs to form their participle also have slightly different forms:

Infinitiv  → Präteritum → Konjunktiv II
brennen → brannte      → brennte
bringen  → brachte      → brächte
denken  → dachte        → dächte
kennen →  kannte        → kennte
nennen → nannte         → nennte
rennen  → rannte          → rennte

It is worth noting that some mixed verbs whose stem vowels change from ‘e’ to ‘a’ and then back to ‘e’ typically use “würden” + Infinitiv” instead of the subjunctive forms listed above, for example: Ich würde denken/bringen/rennen (I would think/bring/run). 

3. Use of “wenn” (if)

The subordinating conjunction “wenn” occurs frequently in combination with the subjunctive; however, the same way that it can in English, there are times when it can be omitted in German.

Examples:
Wenn ich weniger Stress hätte, würde ich besser schlafen
If I had less stress, I would sleep better.

Hätte ich weniger Stress, (dann*) würde ich besser schlafen.
Had I less stress, then I would sleep better.

Wenn ich jünger wäre, könnte ich mehr Sport treiben.
If I were younger, I could do more sports.

Wäre ich jünger, dann* könnte ich mehr Sport treiben. / Were I younger, then I could do more sports.

* “dann” and “so” (more literary) are particles that precede the expected conjugated verb in the main clause, but take up no position (i.e. do not affect word order)

In the second and fourth sentences, “wenn” is dropped, but either “dann” or “so” is added after the comma at the beginning of the main clause. There is not much difference in the sentences and their meanings.

Sometimes “wenn”-clauses stand on their own without any main clause

Examples:
Wenn ich nur jünger wäre!  or  Wäre ich nur jünger!
 If I were only younger! 
Wenn ich nur mehr Zeit hätte!  or  Hätte ich nur mehr Zeit!
If I only had more time! 
Wenn du mich nur sehen könntest!  or  Könntest du mich nur sehen!
If you could only see me!