To declare something "untranslatable" is essentially to imply that a non-native speaker is incapable of understanding it no matter how much they study the language. It deals in "touchy feely unquantifiable nonsense".
Noticed that everyone in here who proclaims that some things are untranslatable have yet to provide actual concrete examples of them (SRC LANG, TGT LANG, SRC SENTENCE)
The fact that you can have legal documents translated from one language to another is all the proof you need that if you're a good enough translator, all languages are interchangeable. You might need a whole lot more words or a whole lot less words depending on the source and target language though.