[schoen]

I don't know enough German to be sure of a rule about when the -ung form does and doesn't occur, but I can think of verbs that don't have it (confirmed with grep!), so it's not completely productive. (First examples offhand: essen, haben, denken, gehen, although the latter does seem to do -ung with some prefixes.)

It's also interesting to think of how to describe the semantic difference between the -en and -ung nouns when both do exist. I think one case is that the -ung can often describe the result of completing the action of the verb or in some sense refer to a "complete instance" or "complete occasion" of the verb's action, but this is generalizing from just a few examples...

[schoen]

Wiktionary seems to agree with my guess about the meaning of -ung:

> forms nouns from verbs, usually describing either an event in which an action is carried out, or the result of that action.

> Note that the -ung suffixed form is different from the gerund which is formed by simply capitalizing the first letter of the verb. The gerund usually refers to the activity in general rather than a specific instance or result.

[seabass-labrax]

The -ung words also feel slightly more technical to me. When you read laws, for instance, there are quite a lot of 'ungs', more so perhaps than in colloquial writing. Maybe that is because, as you put it, "completing the action of the verb" has a more abstract meaning that referring to a specific act. In English, it feels to me like we too would (in laws, for instance) be more wont to use the '-tion' form of a verb rather than the '-ing' gerund. Perhaps also that, the longer the word, the more technical it feels in any language :)

[schoen]

That's interesting. "Completion" vs. "completing".

I tried this to get all of the dictionary pairs for comparison:

  import re

  german = set(open("/usr/share/dict/ngerman").read().split())
  english = set(open("/usr/share/dict/words").read().split())

  tech_de = "ung"
  gerund_de = "en"

  tech_en = "tion"
  gerund_en = "ting"

  for word in sorted(list(german)):
      if word[0].isupper() and word.endswith(tech_de):
          gerund = re.sub(tech_de + "$", gerund_de, word)
          if gerund in german:
              print(word, gerund)
  
  print()
  
  for word in sorted(list(english)):
      if word[0].islower() and word.endswith(tech_en):
          gerund = re.sub(tech_en + "$", gerund_en, word)
          if gerund in english:
              print(word, gerund)

Unfortunately the English pairs aren't quite complete because the morphological change isn't always simply a matter of s/tion$/ting/, but we get a large number of pairs in each language to look at!

I put a sample output of this up at https://sethschoen.com/gerund-comparison.txt in case anyone wants to look at it (not promising to keep it there forever!). (Note the default character encoding from the web server is wrong so you may have to change encodings manually, or download the file and reopen it, to see German umlaut characters correctly.)