> I don't know any other language where flexible argument order would work so well.

What kind of sample size is that? A case system and flexible argument order are largely the same thing.

Note also that flexible argument order is a robust phenomenon in English:

1. Colonel Mustard killed him in the study at 5:00 with his own knife.

2. Colonel Mustard killed him at 5:00 in the study with his own knife.

3. Colonel Mustard killed him in the study with his own knife at 5:00.

4. Colonel Mustard killed him with his own knife at 5:00 in the study.

5. Colonel Mustard killed him at 5:00 with his own knife in the study.

6. Colonel Mustard killed him with his own knife in the study at 5:00.

But if you insist on looking in other languages, there's a famous Latin poem beginning Quis multa gracilis te puer in rosa perfusus liquidis urget odoribus grato, Pyrrha, sub antro?

Translating this as closely as possible to a one-word-for-one-word standard, it says What slender boy soaked [in] liquid odors presses you among many rose[s], Pyrrha, beneath [a] pleasant cave?

(Notes: rosa is singular for unclear reasons. There is nothing corresponding to the in of "in liquid odors"; the relationship between the odors and the soaking is expressed purely by case. There is also nothing corresponding to the article in "a pleasant cave"; Latin does not mark definiteness in this way. Location inside a cave is expressed with "beneath"; compare English underwater.)

Anyway, the actual word ordering, using this translation, is: What many slender you boy among rose[s] soaked liquid presses [in-]odors pleasant, Pyrrha, beneath [a-]cave?

I've heard that Russian poetry is given to similarly intricate word orderings.