It is just a question of orthography. In German, compound nouns are written without space, as a single word. In English, they are usually (but not always) written with space. So "Christmas tree" is "Weinachtsbaum". This is sometimes made out to be much more mysterious than it is, as if German is more "composable" or something, but the only difference is the typographical space.
English is just more difficult to spell because there no simple rule for when a compound is written with or without space (or with a dash, as is sometimes the case). E.g. Christmas is Christ + mass, but is written in a single word.
It's not just orthography. English has been influenced by Romance languages and gained a tendency to write "of"s instead of compounds. This reverses the word order (order of words) and adds extra words in between.
There is some bit of composability that German has over English though. It's just easier to pick apart words that have been concatenated. Maybe it's because often the first word is in genitive (roughly means possessive) form?
In your example, "Weinachtsbaum", we have "Weinnacht" (itself a compound wine-night) meaning Christmas, and we have "Baum", tree. But the word gets and extra "s" in the middle which is serving roughly the same purpose as "'s" in English.
Winenight'stree. Tree of night of wine. I prefer the Germanic construction.
While you are correct to some extent, I do find German to be much more consistent in this regard.
In many cases this may just be due to English's distance from it's root (i.e. Latin, French). As it was pointed out below, "syntax" is also a composition of two simpler words - they just aren't words we know. In German, there are also loan words from Latin and French, but I do have the impression it is not to the same extent, and the German language is quite consistent.
As a German native speaker I find German much more confusing in this regard.
Maybe this is because I don't know the rules in English well enough[1] but for German I can give you a few examples of the complications we have to deal with:
From grandparent:
> In German, compound nouns are written without space, as a single word.
This is true, but the difficulty is to know when two or more nouns are considered a compound noun (Zusammensetzung) or just a group of words (Wortgruppe).
For example consider the following (real) street names:
- Schleißheimer Straße
- Hohenzollernstraße
- Leuchtenbergerstraße
Straße is simply street. Schleißheim is the name of a place.
Schleißheimer Straße is written as two separate words because the rule [2]
says that combinations with geographic names ending in -er that signify a place
(and not the people living in that place, for example) are usually not
considered compounds. A simple counterexample would be Hohenzollernstraße with Hohenzollern referring to the House of Hohenzollern.
Now consider a case like Leuchtenbergerstraße. Leuchtenberger can refer to the place called Leuchtenberg or the Duke of Leuchtenberg. It would be written Leuchtenberger Straße if it had
to do anything with the city of Leuchtenberg, maybe leading to that place. If it is named in the honor of the Duke it would be written Leuchtenbergerstraße.
Another problem is that often nouns are not simply slapped together.
Adding an additional s (Fugen-s[3]) between the words is very common.
For example:
traffic is Verkehr, sign is Zeichen, traffic sign is not Verkehrzeichen but Verkehrszeichen.
On the other hand: tax is Steuer and transfer tax is Verkehrsteuer, but not Verkehrsssteuer.
dog is Hund and leash is Leine. A dog leash is a Hundeleine, addding an additional e in this case.
Sometimes nothing is added but something removed: crown is Krone, prince is Prinz and a crown prince is a Kronprinz, leaving out the final e in Krone.
Compounding in German is complicated and weird.
[1] The only rule i know is: "It's written as two words, except for a few well known exceptions." I suspect that there is more to it and I'd be happy for any enlightenment.
English is just more difficult to spell because there no simple rule for when a compound is written with or without space (or with a dash, as is sometimes the case). E.g. Christmas is Christ + mass, but is written in a single word.