Added a German/Norwegian section — but vidarh corrected me below: German doesn't 'remove the space,' the compound never had one. Adding a space changes the meaning or breaks the grammar. The article now reflects that.

The issue with German as well as Norwegian is that a space creates a semantically distinct structure, so it's not that they remove the space, but that one wasn't there in the first place, and some of those compounds then become important enough for the dictionary.

Absolutely not all - there's a near unbounded set of possible compounds.

In Norwegian, we in fact have a compound for the incorrect separation of compounds: "orddelingsfeil" (word separation error). Actually, we have two - technically it's "særskrivingsfeil" (separate writing error), but "orddelingsfeil" is more common... We take this seriously.

The problem is that while some are definitely wrong, others change meaning.

E.g. "en norsk lærer" means "a Norwegian teacher" but "en norsklærer" means "a teacher of the subject Norwegian". There's an infinite set of possible -lærer compounds: If you create a new subject then a teacher of that subject is a <subject>lærer. Obviously they can't all go in the dictionary.

Some other examples:

"Røyk fritt" means "smoke freely" while "røykfritt" means "smokefree". "Steke ovn", means "to fry an oven", while "stekeovn" means "oven". These two belong in the dictionary because they are so common and that though technically you can use "ovn" and "fri"/"fritt" to form a near infinite number of other common forms as well, in practice the number of common forms that use them is quite limited.

The key part is that most compounds in languages like German or Norwegian will only have one valid way of writing them. Add spaces, and you usually end up with something ungrammatical or with an entirely different meaning.

Whereas in English whether or not a word can be written with a space, with a hyphen, or combined much more often changes over time, and can differ in different places at different times, as the <separate words> -> <hyphenated> -> <compound> pipeline in English is slow and arbitrary and not necessarily reflecting a change in meaning.

I just adapted your comments into the paragraph starting with "German". Hopefully accurately.

And we don't expect dictionaries to contain every compound word you could come up with in German either.

Not the ones that someone could come up with, just the ones people do use.

Your examples are ridiculous though.. The meaning of "[G]esundheitszeugnis" can be derived if you understand the 2 words.

Meanwhile, a Bahnhof would be a "Yard/square of lanes" if one didn't get taught that it's "train station". Although I suppose anyone learning German will quickly learn that "Bahn" is something to do with trains. Unless it's Autobahn. Or Schwimmbahn.

Why are they ridiculous? Words that get used, get used, the etymology is a curiosity to most. In English, we use "computer" even though it used to be a job title. Native English speakers freely use "rucksack" even though it was stolen from German and even though "backpack" is also available, without the space, as a compound English word for a pack worn on the back. English/German has "briefcase"/"Briefkasten" to describe a box that letters go in, it's just that the former is for transporting letters and the latter is for receiving them.